--- _id: '10075' abstract: - lang: eng text: We study the expressiveness and succinctness of good-for-games pushdown automata (GFG-PDA) over finite words, that is, pushdown automata whose nondeterminism can be resolved based on the run constructed so far, but independently of the remainder of the input word. We prove that GFG-PDA recognise more languages than deterministic PDA (DPDA) but not all context-free languages (CFL). This class is orthogonal to unambiguous CFL. We further show that GFG-PDA can be exponentially more succinct than DPDA, while PDA can be double-exponentially more succinct than GFG-PDA. We also study GFGness in visibly pushdown automata (VPA), which enjoy better closure properties than PDA, and for which we show GFGness to be ExpTime-complete. GFG-VPA can be exponentially more succinct than deterministic VPA, while VPA can be exponentially more succinct than GFG-VPA. Both of these lower bounds are tight. Finally, we study the complexity of resolving nondeterminism in GFG-PDA. Every GFG-PDA has a positional resolver, a function that resolves nondeterminism and that is only dependant on the current configuration. Pushdown transducers are sufficient to implement the resolvers of GFG-VPA, but not those of GFG-PDA. GFG-PDA with finite-state resolvers are determinisable. acknowledgement: 'Ismaël Jecker: Funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 754411. Karoliina Lehtinen: Funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 892704.' alternative_title: - LIPIcs article_number: '53' article_processing_charge: No author: - first_name: Shibashis full_name: Guha, Shibashis last_name: Guha - first_name: Ismael R full_name: Jecker, Ismael R id: 85D7C63E-7D5D-11E9-9C0F-98C4E5697425 last_name: Jecker - first_name: Karoliina full_name: Lehtinen, Karoliina last_name: Lehtinen - first_name: Martin full_name: Zimmermann, Martin last_name: Zimmermann citation: ama: 'Guha S, Jecker IR, Lehtinen K, Zimmermann M. A bit of nondeterminism makes pushdown automata expressive and succinct. In: 46th International Symposium on Mathematical Foundations of Computer Science. Vol 202. Schloss Dagstuhl - Leibniz Zentrum für Informatik; 2021. doi:10.4230/LIPIcs.MFCS.2021.53' apa: 'Guha, S., Jecker, I. R., Lehtinen, K., & Zimmermann, M. (2021). A bit of nondeterminism makes pushdown automata expressive and succinct. In 46th International Symposium on Mathematical Foundations of Computer Science (Vol. 202). Tallinn, Estonia: Schloss Dagstuhl - Leibniz Zentrum für Informatik. https://doi.org/10.4230/LIPIcs.MFCS.2021.53' chicago: Guha, Shibashis, Ismael R Jecker, Karoliina Lehtinen, and Martin Zimmermann. “A Bit of Nondeterminism Makes Pushdown Automata Expressive and Succinct.” In 46th International Symposium on Mathematical Foundations of Computer Science, Vol. 202. Schloss Dagstuhl - Leibniz Zentrum für Informatik, 2021. https://doi.org/10.4230/LIPIcs.MFCS.2021.53. ieee: S. Guha, I. R. Jecker, K. Lehtinen, and M. Zimmermann, “A bit of nondeterminism makes pushdown automata expressive and succinct,” in 46th International Symposium on Mathematical Foundations of Computer Science, Tallinn, Estonia, 2021, vol. 202. ista: 'Guha S, Jecker IR, Lehtinen K, Zimmermann M. 2021. A bit of nondeterminism makes pushdown automata expressive and succinct. 46th International Symposium on Mathematical Foundations of Computer Science. MFCS: Mathematical Foundations of Computer Science, LIPIcs, vol. 202, 53.' mla: Guha, Shibashis, et al. “A Bit of Nondeterminism Makes Pushdown Automata Expressive and Succinct.” 46th International Symposium on Mathematical Foundations of Computer Science, vol. 202, 53, Schloss Dagstuhl - Leibniz Zentrum für Informatik, 2021, doi:10.4230/LIPIcs.MFCS.2021.53. short: S. Guha, I.R. Jecker, K. Lehtinen, M. Zimmermann, in:, 46th International Symposium on Mathematical Foundations of Computer Science, Schloss Dagstuhl - Leibniz Zentrum für Informatik, 2021. conference: end_date: 2021-08-27 location: Tallinn, Estonia name: 'MFCS: Mathematical Foundations of Computer Science' start_date: 2021-08-23 date_created: 2021-10-03T22:01:23Z date_published: 2021-08-18T00:00:00Z date_updated: 2022-05-13T08:21:56Z day: '18' ddc: - '000' department: - _id: KrCh doi: 10.4230/LIPIcs.MFCS.2021.53 ec_funded: 1 external_id: arxiv: - '2105.02611' file: - access_level: open_access checksum: f4d407d43a97330c3fb11e6a7a6fbfb2 content_type: application/pdf creator: cchlebak date_created: 2021-10-06T12:44:05Z date_updated: 2021-10-06T12:44:05Z file_id: '10097' file_name: 2021_LIPIcs_Guha.pdf file_size: 825567 relation: main_file success: 1 file_date_updated: 2021-10-06T12:44:05Z has_accepted_license: '1' intvolume: ' 202' language: - iso: eng month: '08' oa: 1 oa_version: Published Version project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: 46th International Symposium on Mathematical Foundations of Computer Science publication_identifier: isbn: - 978-3-9597-7201-3 issn: - 1868-8969 publication_status: published publisher: Schloss Dagstuhl - Leibniz Zentrum für Informatik quality_controlled: '1' scopus_import: '1' status: public title: A bit of nondeterminism makes pushdown automata expressive and succinct tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 202 year: '2021' ...