@article{20223, abstract = {The first influential hypothesis for sex chromosome evolution was proposed in 1914 by H. J. Muller, who argued that once recombination was suppressed between the X and Y chromosomes, Y-linked genes become “sheltered” from selection, leading to accumulation of recessive loss-of-function (LOF) mutations and decay of Y-linked genes. The hypothesis fell out of favor in the 1970s because early mathematical models failed to support it and data on the dominance of lethal mutations were viewed as incompatible with the hypothesis. We reevaluate the main arguments against Muller's hypothesis and find that they do not conclusively exclude a role for sheltering in sex chromosome evolution. By relaxing restrictive assumptions of earlier models, we show that sheltering promotes fixation of LOF mutations with sexually dimorphic fitness effects, resulting in decay of X-linked genes that are exclusively expressed by males and Y-linked genes that are primarily, though not necessarily exclusively, expressed by females. We further show that drift and other processes contributing to Y degeneration (i.e. selective interference and regulatory evolution) expand conditions of Y-linked gene loss by sheltering. The actual contribution of sheltering to sex chromosome evolution hinges upon the distribution of dominance and sex-specific fitness effects of LOF mutations, which we discuss.}, author = {Mrnjavac, Andrea and Vicoso, Beatriz and Connallon, Tim}, issn = {1537-1719}, journal = {Molecular Biology and Evolution}, number = {8}, publisher = {Oxford University Press}, title = {{An extension of Muller's sheltering hypothesis for the evolution of sex chromosome gene content}}, doi = {10.1093/molbev/msaf177}, volume = {42}, year = {2025}, } @inproceedings{20224, abstract = {Traffic in datacenters may follow some pattern: some pairs of servers communicate more frequently than others. Demand-oblivious networks may perform poorly for such workloads, and demand-aware networks optimized for traffic should be used instead. Unfortunately, not all shapes of networks are feasible in real hardware. Practical limitations are usually provided in the form of a topology. For example, a network may be required to be a binary tree, a bounded-degree graph or a Fat tree. In this work, we consider a topology of a binary tree, one of the most fundamental network topologies. We show that already finding an optimal demand-aware binary tree network is NP-hard. Then, we explore how various optimization techniques, including simple local searches, as well as deterministic mutation and crossover operators, cope with generating efficient tree networks on real-life and synthetic workloads.}, author = {Martynov, Pavel and Buzdalov, Maxim and Pankratov, Sergei and Aksenov, Vitaliy and Schmid, Stefan}, booktitle = {Proceedings of the 2025 Genetic and Evolutionary Computation Conference}, isbn = {9798400714658}, location = {Malaga, Spain}, pages = {249--257}, publisher = {Association for Computing Machinery}, title = {{In the search of optimal tree networks: Hardness and heuristics}}, doi = {10.1145/3712256.3726425}, year = {2025}, } @inproceedings{20225, abstract = {We present the first supermartingale certificate for quantitative -regular properties of discrete-time infinite-state stochastic systems. Our certificate is defined on the product of the stochastic system and a limit-deterministic Büchi automaton that specifies the property of interest; hence we call it a limit-deterministic Büchi supermartingale (LDBSM). Previously known supermartingale certificates applied only to quantitative reachability, safety, or reach-avoid properties, and to qualitative (i.e., probability 1) -regular properties.We also present fully automated algorithms for the template-based synthesis of LDBSMs, for the case when the stochastic system dynamics and the controller can be represented in terms of polynomial inequalities. Our experiments demonstrate the ability of our method to solve verification and control tasks for stochastic systems that were beyond the reach of previous supermartingale-based approaches.}, author = {Henzinger, Thomas A and Mallik, Kaushik and Sadeghi, Pouya and Zikelic, Dorde}, booktitle = {37th International Conference on Computer Aided Verification}, isbn = {9783031986789}, issn = {1611-3349}, location = {Zagreb, Croatia}, pages = {29--55}, publisher = {Springer Nature}, title = {{Supermartingale certificates for quantitative omega-regular verification and control}}, doi = {10.1007/978-3-031-98679-6_2}, volume = {15932}, year = {2025}, } @phdthesis{20234, abstract = {Game Theory is the mathematical formalization of social dynamics - systems where agents interact over time and the evolution of the state of the system depends on the decisions of every player. This thesis takes the perspective of a single player and focuses on what they can guarantee in the worst case over the behavior of other players. In other words, we consider that the objective of every other player in the game is exactly the opposite to the player. We focus on sustained interactions over time, where the players repeatedly obtain quantitative rewards over time, and they are interested in maximizing their long-term performance. Formally, this thesis focuses on zero-sum games with the liminf average objective. Two fundamental questions that Game Theory aims to answer are the following. 1. How much can a player guarantee to obtain after the interaction? 2. How to act in order to obtain the previously mentioned guarantee? These questions are formalized by the concepts of "value" and "optimal strategies". We study their properties on games that exhibit one or more of the following properties. 1. Partial Observation: the players can not perfectly observe the current state of the system during the game. We consider the model of (finite) Partially Observable Markov Decision Processes and prove that finite-memory strategies are sufficient to approximately guarantee the value. 2. Perturbed Description: the formal description of the game is perturbed by a small parameter. We consider the model of (finite) Perturbed Matrix Games, and provide algorithms to check various robustness properties and to compute the parameterized value and optimal strategies. 3. Stochastic Transitions: the actions of the players determine the behavior of the evolution of the system, described as a probability distribution over the next state. We consider the model of (finite) Perturbed Stochastic Games and provide formulas for the marginal value. 4. Infinite States: the system can be in infinitely many states. We consider the model of Random Dynamic Games on a class of infinite graphs, prove the existence of the value, and quantify the concentration of finite-horizon values.}, author = {Saona Urmeneta, Raimundo J}, issn = {2663-337X}, pages = {125}, publisher = {Institute of Science and Technology Austria}, title = {{Robustness of solutions in game theory : Values and strategies in partially observable, perturbed, stochastic, and infinite games}}, doi = {10.15479/AT-ISTA-20234}, year = {2025}, } @misc{20242, abstract = {This repository contains calculations of carbon footprints of NMR conferences, as described in the article by Lucky N. Kapoor, Natalia Ruzickova, Predrag Živadinović, Valentin Leitner, Maria Anna Sisak, Cecelia Mweka, Jeroen Dobbelaere, Georgios Katsaros, and Paul Schanda Published in Magnetic Resonance, 2025.}, author = {Schanda, Paul}, keywords = {sustainability, conference travel}, publisher = {Institute of Science and Technology Austria}, title = {{Data of: "Quantifying the carbon footprint of conference travel: the case of NMR meetings"}}, doi = {10.15479/AT-ISTA-20242}, year = {2025}, } @article{20249, abstract = {We develop a heuristic for the density of integer points on affine cubic surfaces. Our heuristic applies to smooth surfaces defined by cubic polynomials that are log K3, but it can also be adjusted to handle singular cubic surfaces. We compare our heuristic to Heath-Brown’s prediction for sums of three cubes, as well as to asymptotic formulae in the literature around Zagier’s work on the Markoff cubic surface, and work of Baragar and Umeda on further surfaces of Markoff-type. We also test our heuristic against numerical data for several families of cubic surfaces.}, author = {Browning, Timothy D and Wilsch, Florian Alexander}, issn = {1420-9020}, journal = {Selecta Mathematica New Series}, number = {4}, publisher = {Springer Nature}, title = {{Integral points on cubic surfaces: heuristics and numerics}}, doi = {10.1007/s00029-025-01074-1}, volume = {31}, year = {2025}, } @article{20250, abstract = {Population III stars are possible precursors to early supermassive black holes (BHs). The presence of soft UV Lyman–Werner (LW) background radiation can suppress Population III star formation in minihaloes and allow them to form in pristine atomic-cooling haloes. In the absence of molecular hydrogen (⁠H2⁠) cooling, atomic-cooling haloes enable rapid collapse with suppressed fragmentation. High background LW fluxes from preceding star-formation have been proposed to dissociate H2⁠. This flux can be supplemented by LW radiation from one or more Population III star(s) in the same halo, reducing the necessary background level. Here, we consider atomic-cooling haloes in which multiple protostellar cores form close to one another nearly simultaneously. We assess whether the first star’s LW radiation can dissociate nearby ⁠, enabling rapid accretion on to a nearby protostellar core, and the prompt formation of a second, supermassive star (SMS) from warm, atomically-cooled gas. We use a set of hydrodynamical simulations with the code enzo, with identical LW backgrounds centred on a halo with two adjacent collapsing gas clumps. When an additional large local LW flux is introduced, we observe immediate reductions in both the accretion rates and the stellar masses that form within these clumps. While the LW flux reduces the H2 fraction and increases the gas temperature, the halo core’s potential well is too shallow to promptly heat the gas to >1000 K and increase the second protostar’s accretion rate. We conclude that this internal LW feedback scenario is unlikely to facilitate SMS or massive BH seed formation.}, author = {Sullivan, James and Haiman, Zoltán and Kulkarni, Mihir and Visbal, Eli}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {2}, pages = {822--838}, publisher = {Oxford University Press}, title = {{Can supermassive stars form in protogalaxies due to internal Lyman-Werner feedback?}}, doi = {10.1093/mnras/staf1269}, volume = {542}, year = {2025}, } @article{20251, abstract = {The Lane–Emden inequality controls (math. formular) in terms of the L^1 and L^p norms of p. We provide a remainder estimate for this inequality in terms of a suitable distance of p to the manifold of optimizers.}, author = {Carlen, Eric and Lewin, Mathieu and Lieb, Elliott H. and Seiringer, Robert}, issn = {1432-0835}, journal = {Calculus of Variations and Partial Differential Equations}, number = {7}, publisher = {Springer Nature}, title = {{Stability estimate for the Lane–Emden inequality}}, doi = {10.1007/s00526-025-03062-x}, volume = {64}, year = {2025}, } @article{20252, abstract = {Zirconia nanocrystals (ZrO2 NCs) are a stable host material for lanthanides, but their performance lags behind that of the leading NaYF4 nanomaterials. Here, we leverage surface chemistry and core/shell architectures to uncover the contribution of dopants at the nanocrystal surface and of dopants in the nanocrystal bulk. We first assess the doping efficiency by ICP and find that, while Eu is almost quantitatively incorporated, the other lanthanides (La, Ce, Tb, Tm, Er, Yb) have about 50% incorporation efficiency over the studied doping range of 1–10%. We then determine the nanocrystal surface chemistry using NMR spectroscopy, despite the additional spectral line broadening caused by the paramagnetic lanthanide dopants. By varying the surface ligands and measuring the photoluminescence, we resolve the spectroscopic signals that are sensitive to a change in surface chemistry. Time-resolved emission spectra further reinforce the notion of a bulk component with a long luminescent lifetime and a surface component with a fast lifetime. Upon shelling Eu- or Tb-doped zirconia NCs with pure zirconia, the surface component disappears, and the photoluminescence quantum yield increases. We further functionalized the surface of the core/shell particles with oleylphosphonic acid ligands to obtain excellent dispersibility. These results show that lanthanide-doped zirconia NCs can be engineered to eliminate deactivation pathways.}, author = {Reichholf, Nico and Horta, Sharona and Van Der Heggen, David and Seno, Carlotta and Pulparayil Mathew, Jikson and Ibáñez, Maria and Smet, Philippe F. and De Roo, Jonathan}, issn = {1936-086X}, journal = {ACS Nano}, number = {33}, pages = {30371--30382}, publisher = {American Chemical Society}, title = {{Identification and elimination of surface emission in lanthanide (Co)doped zirconia nanocrystals}}, doi = {10.1021/acsnano.5c09137}, volume = {19}, year = {2025}, } @inproceedings{20253, abstract = {A quantitative word automaton (QWA) defines a function from infinite words to values. For example, every infinite run of a limit-average QWA 𝒜 obtains a mean payoff, and every word w ∈ Σ^ω is assigned the maximal mean payoff obtained by nondeterministic runs of 𝒜 over w. We introduce quantitative language automata (QLAs) that define functions from language generators (i.e., implementations) to values, where a language generator can be nonprobabilistic, defining a set of infinite words, or probabilistic, defining a probability measure over infinite words. A QLA consists of a QWA and an aggregator function. For example, given a QWA 𝒜, the infimum aggregator maps each language L ⊆ Σ^ω to the greatest lower bound assigned by 𝒜 to any word in L. For boolean value sets, QWAs define boolean properties of traces, and QLAs define boolean properties of sets of traces, i.e., hyperproperties. For more general value sets, QLAs serve as a specification language for a generalization of hyperproperties, called quantitative hyperproperties. A nonprobabilistic (resp. probabilistic) quantitative hyperproperty assigns a value to each set (resp. distribution) G of traces, e.g., the minimal (resp. expected) average response time exhibited by the traces in G. We give several examples of quantitative hyperproperties and investigate three paradigmatic problems for QLAs: evaluation, nonemptiness, and universality. In the evaluation problem, given a QLA 𝔸 and an implementation G, we ask for the value that 𝔸 assigns to G. In the nonemptiness (resp. universality) problem, given a QLA 𝔸 and a value k, we ask whether 𝔸 assigns at least k to some (resp. every) language. We provide a comprehensive picture of decidability for these problems for QLAs with common aggregators as well as their restrictions to ω-regular languages and trace distributions generated by finite-state Markov chains.}, author = {Henzinger, Thomas A and Kebis, Pavol and Mazzocchi, Nicolas Adrien and Sarac, Naci E}, booktitle = {36th International Conference on Concurrency Theory}, isbn = {9783959773898}, issn = {1868-8969}, location = {Aarhus, Denmark}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Quantitative language automata}}, doi = {10.4230/LIPIcs.CONCUR.2025.21}, volume = {348}, year = {2025}, } @article{20254, abstract = {We examine population structures for their ability to maintain diversity in neutral evolution. We use the general framework of evolutionary graph theory and consider birth–death (bd) and death–birth (db) updating. The population is of size N. Initially all individuals represent different types. The basic question is: what is the time TN until one type takes over the population? This time is known as consensus time in computer science and as total coalescent time in evolutionary biology. For the complete graph, it is known that TN is quadratic in N for db and bd. For the cycle, we prove that TN is cubic in N for db and bd. For the star, we prove that TN is cubic for bd and quasilinear (N log N) for db. For the double star, we show that TN is quartic for bd. We derive upper and lower bounds for all undirected graphs for bd and db. We also show the Pareto front of graphs (of size N = 8) that maintain diversity the longest for bd and db. Further, we show that some graphs that quickly homogenize can maintain high levels of diversity longer than graphs that slowly homogenize. For directed graphs, we give simple contracting star-like structures that have superexponential time scales for maintaining diversity.}, author = {Brewster, David A. and Svoboda, Jakub and Roscow, Dylan and Chatterjee, Krishnendu and Tkadlec, Josef and Nowak, Martin A.}, issn = {2752-6542}, journal = {PNAS Nexus}, number = {8}, publisher = {Oxford University Press}, title = {{Maintaining diversity in structured populations}}, doi = {10.1093/pnasnexus/pgaf252}, volume = {4}, year = {2025}, } @article{20255, abstract = {With stunning clarity, the JWST has revealed the Universe’s first billion years. The scientific community is analysing a wealth of JWST imaging and spectroscopic data from that era, and is in the process of rewriting the astronomy textbooks. Here, as a result of the 2024 ISSI Breakthrough Workshop, we provide a snapshot of the great progress made towards understanding the initial chapters of our cosmic history 1.5 years into the JWST science mission. We present the current census of early galaxies, their luminosities, appearance, chemical composition, masses and formation histories as revealed by JWST. We relate the discovery of massive black holes in early galaxies and discuss their demographics and implications for their formations and growth. We conclude by describing the potential sources of reionization and our current understanding of how the Universe became fully ionized. Throughout the Perspective, we highlight discoveries and breakthroughs, topics and issues that are not yet understood, and questions that will be addressed in the coming years, as JWST continues its revolutionary observations of the early Universe.}, author = {Adamo, Angela and Atek, Hakim and Bagley, Micaela B. and Bañados, Eduardo and Barrow, Kirk S.S. and Berg, Danielle A. and Bezanson, Rachel and Bradač, Maruša and Brammer, Gabriel and Carnall, Adam C. and Chisholm, John and Coe, Dan and Dayal, Pratika and Eisenstein, Daniel J. and Eldridge, Jan J. and Ferrara, Andrea and Fujimoto, Seiji and Graaff, Anna De and Habouzit, Melanie and Hutchison, Taylor A. and Kartaltepe, Jeyhan S. and Kassin, Susan A. and Kriek, Mariska and Labbé, Ivo and Maiolino, Roberto and Marques-Chaves, Rui and Maseda, Michael V. and Mason, Charlotte and Matthee, Jorryt J and Mcquinn, Kristen B.W. and Meynet, Georges and Naidu, Rohan P. and Oesch, Pascal A. and Pentericci, Laura and Pérez-González, Pablo G. and Rigby, Jane R. and Roberts-Borsani, Guido and Schaerer, Daniel and Shapley, Alice E. and Stark, Daniel P. and Stiavelli, Massimo and Strom, Allison L. and Vanzella, Eros and Wang, Feige and Wilkins, Stephen M. and Williams, Christina C. and Willott, Chris J. and Wylezalek, Dominika and Nota, Antonella}, issn = {2397-3366}, journal = {Nature Astronomy}, number = {8}, pages = {1134--1147}, publisher = {Springer Nature}, title = {{The first billion years according to JWST}}, doi = {10.1038/s41550-025-02624-5}, volume = {9}, year = {2025}, } @inproceedings{20256, abstract = {We study the problem of predictive runtime monitoring of black-box dynamical systems with quantitative safety properties. The black-box setting stipulates that the exact semantics of the dynamical system and the controller are unknown, and that we are only able to observe the state of the controlled (aka, closed-loop) system at finitely many time points. We present a novel framework for predicting future states of the system based on the states observed in the past. The numbers of past states and of predicted future states are parameters provided by the user. Our method is based on a combination of Taylor’s expansion and the backward difference operator for numerical differentiation. We also derive an upper bound on the prediction error under the assumption that the system dynamics and the controller are smooth. The predicted states are then used to predict safety violations ahead in time. Our experiments demonstrate practical applicability of our method for complex black-box systems, showing that it is computationally lightweight and yet significantly more accurate than the state-of-the-art predictive safety monitoring techniques.}, author = {Henzinger, Thomas A and Kresse, Fabian and Mallik, Kaushik and Yu, Zhengqi and Zikelic, Dorde}, booktitle = {7th Annual Learning for Dynamics & Control Conference}, issn = {2640-3498}, location = {Ann Arbor, MI, United States}, pages = {804--816}, publisher = {ML Research Press}, title = {{Predictive monitoring of black-box dynamical systems}}, volume = {283}, year = {2025}, } @article{20258, abstract = {The specific introduction of ^1H-^13C or ^1H-^15N moieties into otherwise deuterated proteins holds great potential for high-resolution solution and magic-angle spinning (MAS) NMR studies of protein structure and dynamics. Arginine residues play key roles for example at active sites of enzymes. Taking advantage of a chemically synthesized Arg with a ^13C-^1H2 group in an otherwise deuterated backbone, we demonstrate here the usefulness of proton-detected MAS NMR approaches to probe arginine dynamics. In experiments with crystalline ubiquitin and the 134 kDa tetrameric enzyme malate dehydrogenase we detected a wide range of motions, from sites that are rigid on time scales of at least tens of milliseconds to residues undergoing predominantly nanosecond motions. Spin-relaxation and dipolar-coupling measurements enabled quantitative determination of these dynamics. We observed microsecond dynamics of residue Arg54 in crystalline ubiquitin, whose backbone is known to sample different β-turn conformations on this time scale. The labeling scheme and experiments presented here expand the toolkit for high-resolution proton-detected MAS NMR.}, author = {Rohden, Darja and Napoli, Federico and Kapitonova, Anna and Tatman, Benjamin and Lichtenecker, Roman J. and Schanda, Paul}, issn = {1089-8638}, journal = {Journal of Molecular Biology}, number = {23}, publisher = {Elsevier}, title = {{Arginine dynamics probed by magic-angle spinning NMR with a specific isotope-labeling scheme}}, doi = {10.1016/j.jmb.2025.169379}, volume = {437}, year = {2025}, } @article{20259, abstract = {Cell migration in narrow microenvironments occurs in numerous physiological processes. It involves successive cycles of confinement and release that drive important morphological changes. However, it remains unclear whether migrating cells can retain a memory of their past morphological states that could potentially facilitate their navigation through confined spaces. We demonstrate that local geometry governs a switch between two cell morphologies, thereby facilitating cell passage through long and narrow gaps. We combined cell migration assays on standardized microsystems with biophysical modelling and biochemical perturbations to show that migrating cells have a long-term memory of past confinement events. The morphological cell states correlate across transitions through actin cortex remodelling. These findings indicate that mechanical memory in migrating cells plays an active role in their migratory potential in confined environments.}, author = {Kalukula, Yohalie and Luciano, Marine and Simanov, Gleb and Charras, Guillaume and Brückner, David and Gabriele, Sylvain}, issn = {1745-2481}, journal = {Nature Physics}, pages = {1451--1461}, publisher = {Springer Nature}, title = {{The actin cortex acts as a mechanical memory of morphology in confined migrating cells}}, doi = {10.1038/s41567-025-02980-z}, volume = {21}, year = {2025}, } @article{20260, abstract = {The medial axis of a set consists of the points in the ambient space without a unique closest point in the original set. Since its introduction, the medial axis has been used extensively in many applications as a method of computing a skeleton topologically equivalent to the original set. Unfortunately, one limiting factor in the use of the medial axis of a smooth manifold is that it is not necessarily topologically stable under small perturbations of the manifold. To counter these instabilities, various prunings of the medial axis have been proposed in the computational geometry community. Here, we examine one type of pruning, called burning. Because of the good experimental results it was hoped that the burning method of simplifying the medial axis would be stable. In this work, we show a simple example that dashes such hopes. Based on Bing’s house with two rooms, we demonstrate an isotopy of a shape where the medial axis goes from collapsible to non-collapsible. More precisely, we consider the standard deformation retract from the closed ball to Bing’s house with two rooms, but stop just short of the point where Bing’s house becomes two dimensional. This way we obtain an isotopy from the 3-ball to a thickened version of Bing’s house. Under this isotopy, the medial axis goes from collapsible to non-collapsible. We stress that this isotopy can be made generic, in the sense of singularity theory, as developed by Arnol’d and Thom.}, author = {Chambers, Erin Wolf and Fillmore, Christopher D and Stephenson, Elizabeth R and Wintraecken, Mathijs}, issn = {2730-9657}, journal = {La Matematica}, pages = {811--828}, publisher = {Springer Nature}, title = {{Burning or collapsing the medial axis is unstable}}, doi = {10.1007/s44007-025-00170-0}, volume = {4}, year = {2025}, } @phdthesis{20276, abstract = {Complex 3D shapes can be created by morphing flat 2D configurations. Such deformations either preserve the intrinsic material geometry (e.g., folding paper) or modify it through localized contraction. Once transformed, the 3D shape can be further controlled to achieve a target functionality. A key challenge is to take the material specifications and the actuation process as input to automatically design the target 3D shape and its functionality. This thesis presents two novel computational pipelines for the design and control of shape-morphing structures used to create functional prototypes. The first pipeline borrows from the art of origami to fold paper into intricate shapes and applies this principle to make 3D lighting displays. We introduce, PCBend a computational design approach that covers a surface with individually addressable RGB LEDs, effectively forming a low-resolution surface by folding rigid printed circuit boards (PCBs). We optimize cut patterns on PCBs to act as hinges and co-design LED placement, circuit routing, and fabrication constraints to produce PCB blueprints. The PCBs are fabricated using automated standard manufacturing services with LEDs embedded on them. Finally, the fabricated PCBs are cut along the contour and folded onto a 3D-printed support. The 3D lighting display is then controlled to display complex surface light patterns. Creating 3D shapes through folding is only possible if their planar configuration, called ”unfolding” exists without any distortion or overlap. Existing methods often permit distortion or require multiple patches, which are unsuitable for fabrication pipelines that rely on folding non-stretchable materials. We reinforce such fabrication pipelines by providing a geometric relaxation to the problem, where the input shape is modified to admit overlap-free unfolding. The second fabrication pipeline extends shape morphing to soft robotics by emulating nature’s blueprint of distributed actuation. Inspired by vertebrates, we build musculoskeletal robots using modular active actuators, employing Liquid Crystal Elastomers (LCEs) as shrinkable artificial muscles integrated with 3D-printed bones. The chemical composition of LCEs is altered to enable untethered actuation through infrared radiation, allowing active control of individual muscles and their corresponding bones. The combined motion of individual bones defines the robot’s overall shape and functionality. Our proposed system significantly expands both the design and control spaces of soft robots, which we harness using our computational design tools. We build several physical robots that exhibit complex shape morphing and varied terrain navigation, showcasing the versatility of our pipeline. This thesis explores applications ranging from intricate light patterns displayed on 3D shapes formed by folding rigid PCBs to untethered robots that use contractile muscles to exhibit shape morphing and locomotion. Through these examples, the thesis highlights how computational design and distributed actuation, integrated with novel materials, can transform passive structures into functional prototypes.}, author = {Bhargava, Manas}, isbn = {978-3-99078-065-7}, issn = {2663-337X}, pages = {96}, publisher = {Institute of Science and Technology Austria}, title = {{Design and control of deformable structures : From PCB lighting displays to elastomer robots}}, doi = {10.15479/AT-ISTA-20276}, year = {2025}, } @unpublished{20286, abstract = {Natural organisms utilize distributed actuation through their musculoskeletal systems to adapt their gait for traversing diverse terrains or to morph their bodies for varied tasks. A longstanding challenge in robotics is to emulate this capability of natural organisms, which has motivated the development of numerous soft robotic systems. However, such systems are generally optimized for a single functionality, lack the ability to change form or function on demand, or remain tethered to bulky control systems. To address these limitations, we present a framework for designing and controlling robots that utilize distributed actuation. We propose a novel building block that integrates 3D-printed bones with liquid crystal elastomer (LCE) muscles as lightweight actuators, enabling the modular assembly of musculoskeletal robots. We developed LCE rods that contract in response to infrared radiation, thereby providing localized, untethered control over the distributed skeletal network and producing global deformations of the robot. To fully capitalize on the extensive design space, we introduce two computational tools: one for optimizing the robot's skeletal graph to achieve multiple target deformations, and another for co-optimizing skeletal designs and control gaits to realize desired locomotion. We validate our framework by constructing several robots that demonstrate complex shape morphing, diverse control schemes, and environmental adaptability. Our system integrates advances in modular material building, untethered and distributed control, and computational design to introduce a new generation of robots that brings us closer to the capabilities of living organisms.}, author = {Bhargava, Manas and Hiraki, Takefumi and Strugaru, Irina-Malina and Zhang, Yuhan and Piovarci, Michael and Daraio, Chiara and Iwai, Daisuke and Bickel, Bernd}, booktitle = {arXiv}, title = {{Computational design and fabrication of modular robots with untethered control}}, doi = {10.48550/arXiv.2508.05410}, year = {2025}, } @article{20289, abstract = {Cell and tissue movement in development, cancer invasion, and immune response relies on chemical or mechanical guidance cues. In many systems, this behavior is locally directed by self-generated signaling gradients rather than long-range, prepatterned cues. However, how heterogeneous mixtures of cells interact nonreciprocally and navigate through self-generated gradients remains largely unexplored. Here, we introduce a theoretical framework for the self-organized chemotaxis of heterogeneous cell populations. We find that the relative chemotactic sensitivities of different cell populations control their long-time coupling and comigration dynamics, with boundary conditions such as external cell and attractant reservoirs substantially influencing the migration patterns. Our model predicts an optimal parameter regime that enables robust and colocalized migration. We test our theoretical predictions with in vitro experiments demonstrating the comigration of distinct immune cell populations, and quantitatively reproduce observed migration patterns under wild-type and perturbed conditions. Interestingly, immune cell comigration occurs close to the predicted optimal regime. Finally, we incorporate mechanical interactions into our framework, revealing a nontrivial interplay between chemotactic and mechanical nonreciprocity in driving collective migration. Together, our findings suggest that self-generated chemotaxis is a robust strategy for the navigation of mixed cell populations.}, author = {Ucar, Mehmet C and Zane, Alsberga and Alanko, Jonna H and Sixt, Michael K and Hannezo, Edouard B}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, number = {34}, publisher = {National Academy of Sciences}, title = {{Self-generated chemotaxis of mixed cell populations}}, doi = {10.1073/pnas.2504064122}, volume = {122}, year = {2025}, } @inproceedings{20290, abstract = {We consider equilibria in multiplayer stochastic graph games with terminal-node rewards. In such games, Nash equilibria are defined assuming that each player seeks to maximise their expected payoff, ignoring their aversion or tolerance to risk. We therefore study risk-sensitive equilibria (RSEs), where the expected payoff is replaced by a risk measure. A classical risk measure in the literature is the entropic risk measure, where each player has a real valued parameter capturing their risk-averseness. We introduce the extreme risk measure, which corresponds to extreme cases of entropic risk measure, where players are either extreme optimists or extreme pessimists. Under extreme risk measure, every player is an extremist: an extreme optimist perceives their reward as the maximum payoff that can be achieved with positive probability, while an extreme pessimist expects the minimum payoff achievable with positive probability. We argue that the extreme risk measure, especially in multi-player graph based settings, is particularly relevant as they can model several real life instances such as interactions between secure systems and potential security threats, or distributed controls for safety critical systems. We prove that RSEs defined with the extreme risk measure are guaranteed to exist when all rewards are non-negative. Furthermore, we prove that the problem of deciding whether a given game contains an RSE that generates risk measures within specified intervals is decidable and NP-complete for our extreme risk measure, and even PTIME-complete when all players are extreme optimists, while that same problem is undecidable using the entropic risk measure or even the classical expected payoff. This establishes, to our knowledge, the first decidable fragment for equilibria in simple stochastic games without restrictions on strategy types or number of players.}, author = {Brice, Léonard and Henzinger, Thomas A and Thejaswini, K. S.}, booktitle = {50th International Symposium on Mathematical Foundations of Computer Science}, isbn = {9783959773881}, issn = {1868-8969}, location = {Warsaw, Poland}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Finding equilibria: Simpler for pessimists, simplest for optimists}}, doi = {10.4230/LIPIcs.MFCS.2025.30}, volume = {345}, year = {2025}, }