@article{12311, abstract = {In this note, we prove a formula for the cancellation exponent kv,n between division polynomials ψn and ϕn associated with a sequence {nP}n∈N of points on an elliptic curve E defined over a discrete valuation field K. The formula greatly generalizes the previously known special cases and treats also the case of non-standard Kodaira types for non-perfect residue fields.}, author = {Naskręcki, Bartosz and Verzobio, Matteo}, issn = {1473-7124}, journal = {Proceedings of the Royal Society of Edinburgh Section A: Mathematics}, keywords = {Elliptic curves, Néron models, division polynomials, height functions, discrete valuation rings}, number = {5}, pages = {1646--1660}, publisher = {Cambridge University Press}, title = {{Common valuations of division polynomials}}, doi = {10.1017/prm.2024.7}, volume = {155}, year = {2025}, } @article{20078, abstract = {Let A be an abelian variety defined over a number field K, E/K be an elliptic curve, and ϕ : A → Em be an isogeny defined over K. Let P ∈ A(K) be such that ϕ(P)=(Q1,..., Qm) with RankZ(⟨Q1,...,Qm⟩)=1. We will study a divisibility sequence related to the point P and show its relation with elliptic divisibility sequences.}, author = {Barańczuk, Stefan and Naskręcki, Bartosz and Verzobio, Matteo}, issn = {0022-314X}, journal = {Journal of Number Theory}, pages = {170--183}, publisher = {Elsevier}, title = {{Divisibility sequences related to abelian varieties isogenous to a power of an elliptic curve}}, doi = {10.1016/j.jnt.2025.06.001}, volume = {279}, year = {2025}, } @article{20222, abstract = {Let X be a smooth projective hypersurface defined over Q. We provide new bounds for rational points of bounded height on X. In particular, we show that if X is a smooth projective hypersurface in Pn with n 4 and degree d 50, then the set of rational points on X of height bounded by B have cardinality On,d,ε (Bn−2+ε ). If X is smooth and has degree d 6, we improve the dimension growth conjecture bound. We achieve an analogue result for affine hypersurfaces whose projective closure is smooth.}, author = {Verzobio, Matteo}, issn = {1687-0247}, journal = {International Mathematics Research Notices}, number = {16}, publisher = {Oxford University Press}, title = {{Counting rational points on smooth hypersurfaces with high degree}}, doi = {10.1093/imrn/rnaf249}, volume = {2025}, year = {2025}, } @article{19407, abstract = {We discuss, in a non-Archimedean setting, the distribution of the coefficients of L-polynomials of curves of genus g over Fq . Among other results, this allows us to prove that the Q-vector space spanned by such characteristic polynomials has dimension g + 1. We also state a conjecture about the Archimedean distribution of the number of rational points of curves over finite fields.}, author = {Ballini, Francesco and Lombardo, Davide and Verzobio, Matteo}, issn = {1473-7124}, journal = {Proceedings of the Royal Society of Edinburgh Section A: Mathematics}, publisher = {Cambridge University Press}, title = {{On the L-polynomials of curves over finite fields}}, doi = {10.1017/prm.2025.7}, year = {2025}, } @article{21003, abstract = {We extend work of Heath-Brown and Salberger, based on the determinant method, to provide a uniform upper bound for the number of integral points of bounded height on an affine surface, which are subject to a polynomial congruence condition. This is applied to get a new uniform bound for points on diagonal quadric surfaces, and to a problem about the representation of integers as a sum of four unlike powers.}, author = {Browning, Timothy D and Verzobio, Matteo}, issn = {2397-3129}, journal = {Discrete Analysis}, publisher = {Cambridge: Alliance of Diamond Open Access Journals}, title = {{Counting integer points on affine surfaces with a side condition}}, doi = {10.19086/da.143787}, volume = {2025}, year = {2025}, } @article{12312, abstract = {Let $\ell$ be a prime number. We classify the subgroups $G$ of $\operatorname{Sp}_4(\mathbb{F}_\ell)$ and $\operatorname{GSp}_4(\mathbb{F}_\ell)$ that act irreducibly on $\mathbb{F}_\ell^4$, but such that every element of $G$ fixes an $\mathbb{F}_\ell$-vector subspace of dimension 1. We use this classification to prove that the local-global principle for isogenies of degree $\ell$ between abelian surfaces over number fields holds in many cases -- in particular, whenever the abelian surface has non-trivial endomorphisms and $\ell$ is large enough with respect to the field of definition. Finally, we prove that there exist arbitrarily large primes $\ell$ for which some abelian surface $A/\mathbb{Q}$ fails the local-global principle for isogenies of degree $\ell$.}, author = {Lombardo, Davide and Verzobio, Matteo}, issn = {1420-9020}, journal = {Selecta Mathematica}, number = {2}, publisher = {Springer Nature}, title = {{On the local-global principle for isogenies of abelian surfaces}}, doi = {10.1007/s00029-023-00908-0}, volume = {30}, year = {2024}, } @article{17323, abstract = {We investigate strong divisibility sequences and produce lower and upper bounds for the density of integers in the sequence that only have (somewhat) large prime factors. We focus on the special cases of Fibonacci numbers and elliptic divisibility sequences, discussing the limitations of our methods. At the end of the paper, there is an appendix by Sandro Bettin on divisor closed sets that we use to study the density of prime terms that appear in strong divisibility sequences.}, author = {Browning, Timothy D and Verzobio, Matteo}, issn = {2041-7942}, journal = {Mathematika}, number = {4}, publisher = {London Mathematical Society}, title = {{Strong divisibility sequences and sieve methods}}, doi = {10.1112/mtk.12269}, volume = {70}, year = {2024}, } @article{12313, abstract = {Let P be a nontorsion point on an elliptic curve defined over a number field K and consider the sequence {Bn}n∈N of the denominators of x(nP). We prove that every term of the sequence of the Bn has a primitive divisor for n greater than an effectively computable constant that we will explicitly compute. This constant will depend only on the model defining the curve.}, author = {Verzobio, Matteo}, issn = {0030-8730}, journal = {Pacific Journal of Mathematics}, number = {2}, pages = {331--351}, publisher = {Mathematical Sciences Publishers}, title = {{Some effectivity results for primitive divisors of elliptic divisibility sequences}}, doi = {10.2140/pjm.2023.325.331}, volume = {325}, year = {2023}, } @article{12308, abstract = {Let P and Q be two points on an elliptic curve defined over a number field K. For α∈End(E), define Bα to be the OK-integral ideal generated by the denominator of x(α(P)+Q). Let O be a subring of End(E), that is a Dedekind domain. We will study the sequence {Bα}α∈O. We will show that, for all but finitely many α∈O, the ideal Bα has a primitive divisor when P is a non-torsion point and there exist two endomorphisms g≠0 and f so that f(P)=g(Q). This is a generalization of previous results on elliptic divisibility sequences.}, author = {Verzobio, Matteo}, issn = {2522-0160}, journal = {Research in Number Theory}, keywords = {Algebra and Number Theory}, number = {2}, publisher = {Springer Nature}, title = {{Primitive divisors of sequences associated to elliptic curves with complex multiplication}}, doi = {10.1007/s40993-021-00267-9}, volume = {7}, year = {2021}, } @article{12309, abstract = {Take a rational elliptic curve defined by the equation y2=x3+ax in minimal form and consider the sequence Bn of the denominators of the abscissas of the iterate of a non-torsion point. We show that B5m has a primitive divisor for every m. Then, we show how to generalize this method to the terms of the form Bmp with p a prime congruent to 1 modulo 4.}, author = {Verzobio, Matteo}, issn = {0065-1036}, journal = {Acta Arithmetica}, keywords = {Algebra and Number Theory}, number = {2}, pages = {129--168}, publisher = {Institute of Mathematics, Polish Academy of Sciences}, title = {{Primitive divisors of elliptic divisibility sequences for elliptic curves with j=1728}}, doi = {10.4064/aa191016-30-7}, volume = {198}, year = {2021}, } @unpublished{12314, abstract = {In literature, there are two different definitions of elliptic divisibility sequences. The first one says that a sequence of integers $\{h_n\}_{n\geq 0}$ is an elliptic divisibility sequence if it verifies the recurrence relation $h_{m+n}h_{m-n}h_{r}^2=h_{m+r}h_{m-r}h_{n}^2-h_{n+r}h_{n-r}h_{m}^2$ for every natural number $m\geq n\geq r$. The second definition says that a sequence of integers $\{\beta_n\}_{n\geq 0}$ is an elliptic divisibility sequence if it is the sequence of the square roots (chosen with an appropriate sign) of the denominators of the abscissas of the iterates of a point on a rational elliptic curve. It is well-known that the two sequences are not equivalent. Hence, given a sequence of the denominators $\{\beta_n\}_{n\geq 0}$, in general does not hold $\beta_{m+n}\beta_{m-n}\beta_{r}^2=\beta_{m+r}\beta_{m-r}\beta_{n}^2-\beta_{n+r}\beta_{n-r}\beta_{m}^2$ for $m\geq n\geq r$. We will prove that the recurrence relation above holds for $\{\beta_n\}_{n\geq 0}$ under some conditions on the indexes $m$, $n$, and $r$.}, author = {Verzobio, Matteo}, booktitle = {arXiv}, title = {{A recurrence relation for elliptic divisibility sequences}}, doi = {10.48550/arXiv.2102.07573}, year = {2021}, } @article{12310, abstract = {Let be a sequence of points on an elliptic curve defined over a number field K. In this paper, we study the denominators of the x-coordinates of this sequence. We prove that, if Q is a torsion point of prime order, then for n large enough there always exists a primitive divisor. Later on, we show the link between the study of the primitive divisors and a Lang-Trotter conjecture. Indeed, given two points P and Q on the elliptic curve, we prove a lower bound for the number of primes p such that P is in the orbit of Q modulo p.}, author = {Verzobio, Matteo}, issn = {0022-314X}, journal = {Journal of Number Theory}, keywords = {Algebra and Number Theory}, number = {4}, pages = {378--390}, publisher = {Elsevier}, title = {{Primitive divisors of sequences associated to elliptic curves}}, doi = {10.1016/j.jnt.2019.09.003}, volume = {209}, year = {2020}, }