In symbolic integration, the Risch--Norman algorithm aims to find closed forms of elementary integrals over differential fields by an ansatz for the integral, which usually is based on heuristic degree bounds. Norman presented an approach that avoids degree bounds and only relies on the completion of reduction systems. We give a formalization of his approach and we develop a refined completion process, which terminates in more instances. In some situations when the algorithm does not terminate, one can detect patterns allowing to still describe infinite reduction systems that are complete. We present such infinite systems for the fields generated by Airy functions and complete elliptic integrals, respectively. Moreover, we show how complete reduction systems can be used to find rigorous degree bounds. In particular, we give a general formula for weighted degree bounds and we apply it to find tight bounds for above examples.
{"title":"Reduction systems and degree bounds for integration","authors":"Hao Du, Clemens G. Raab","doi":"arxiv-2404.13042","DOIUrl":"https://doi.org/arxiv-2404.13042","url":null,"abstract":"In symbolic integration, the Risch--Norman algorithm aims to find closed\u0000forms of elementary integrals over differential fields by an ansatz for the\u0000integral, which usually is based on heuristic degree bounds. Norman presented\u0000an approach that avoids degree bounds and only relies on the completion of\u0000reduction systems. We give a formalization of his approach and we develop a\u0000refined completion process, which terminates in more instances. In some\u0000situations when the algorithm does not terminate, one can detect patterns\u0000allowing to still describe infinite reduction systems that are complete. We\u0000present such infinite systems for the fields generated by Airy functions and\u0000complete elliptic integrals, respectively. Moreover, we show how complete\u0000reduction systems can be used to find rigorous degree bounds. In particular, we\u0000give a general formula for weighted degree bounds and we apply it to find tight\u0000bounds for above examples.","PeriodicalId":501033,"journal":{"name":"arXiv - CS - Symbolic Computation","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140635124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We design polynomial size, constant depth (namely, $mathsf{AC}^0$) arithmetic formulae for the greatest common divisor (GCD) of two polynomials, as well as the related problems of the discriminant, resultant, B'ezout coefficients, squarefree decomposition, and the inversion of structured matrices like Sylvester and B'ezout matrices. Our GCD algorithm extends to any number of polynomials. Previously, the best known arithmetic formulae for these problems required super-polynomial size, regardless of depth. These results are based on new algorithmic techniques to compute various symmetric functions in the roots of polynomials, as well as manipulate the multiplicities of these roots, without having access to them. These techniques allow $mathsf{AC}^0$ computation of a large class of linear and polynomial algebra problems, which include the above as special cases. We extend these techniques to problems whose inputs are multivariate polynomials, which are represented by $mathsf{AC}^0$ arithmetic circuits. Here too we solve problems such as computing the GCD and squarefree decomposition in $mathsf{AC}^0$.
{"title":"Constant-Depth Arithmetic Circuits for Linear Algebra Problems","authors":"Robert Andrews, Avi Wigderson","doi":"arxiv-2404.10839","DOIUrl":"https://doi.org/arxiv-2404.10839","url":null,"abstract":"We design polynomial size, constant depth (namely, $mathsf{AC}^0$)\u0000arithmetic formulae for the greatest common divisor (GCD) of two polynomials,\u0000as well as the related problems of the discriminant, resultant, B'ezout\u0000coefficients, squarefree decomposition, and the inversion of structured\u0000matrices like Sylvester and B'ezout matrices. Our GCD algorithm extends to any\u0000number of polynomials. Previously, the best known arithmetic formulae for these\u0000problems required super-polynomial size, regardless of depth. These results are based on new algorithmic techniques to compute various\u0000symmetric functions in the roots of polynomials, as well as manipulate the\u0000multiplicities of these roots, without having access to them. These techniques\u0000allow $mathsf{AC}^0$ computation of a large class of linear and polynomial\u0000algebra problems, which include the above as special cases. We extend these techniques to problems whose inputs are multivariate\u0000polynomials, which are represented by $mathsf{AC}^0$ arithmetic circuits. Here\u0000too we solve problems such as computing the GCD and squarefree decomposition in\u0000$mathsf{AC}^0$.","PeriodicalId":501033,"journal":{"name":"arXiv - CS - Symbolic Computation","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140614861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hector Kohler, Quentin Delfosse, Paul Festor, Philippe Preux
Embracing the pursuit of intrinsically explainable reinforcement learning raises crucial questions: what distinguishes explainability from interpretability? Should explainable and interpretable agents be developed outside of domains where transparency is imperative? What advantages do interpretable policies offer over neural networks? How can we rigorously define and measure interpretability in policies, without user studies? What reinforcement learning paradigms,are the most suited to develop interpretable agents? Can Markov Decision Processes integrate interpretable state representations? In addition to motivate an Interpretable RL community centered around the aforementioned questions, we propose the first venue dedicated to Interpretable RL: the InterpPol Workshop.
{"title":"Towards a Research Community in Interpretable Reinforcement Learning: the InterpPol Workshop","authors":"Hector Kohler, Quentin Delfosse, Paul Festor, Philippe Preux","doi":"arxiv-2404.10906","DOIUrl":"https://doi.org/arxiv-2404.10906","url":null,"abstract":"Embracing the pursuit of intrinsically explainable reinforcement learning\u0000raises crucial questions: what distinguishes explainability from\u0000interpretability? Should explainable and interpretable agents be developed\u0000outside of domains where transparency is imperative? What advantages do\u0000interpretable policies offer over neural networks? How can we rigorously define\u0000and measure interpretability in policies, without user studies? What\u0000reinforcement learning paradigms,are the most suited to develop interpretable\u0000agents? Can Markov Decision Processes integrate interpretable state\u0000representations? In addition to motivate an Interpretable RL community centered\u0000around the aforementioned questions, we propose the first venue dedicated to\u0000Interpretable RL: the InterpPol Workshop.","PeriodicalId":501033,"journal":{"name":"arXiv - CS - Symbolic Computation","volume":"183 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140614865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Semi-algebraic set is a subset of the real space defined by polynomial equations and inequalities. In this paper, we consider the problem of deciding whether two given points in a semi-algebraic set are connected. We restrict to the case when all equations and inequalities are invariant under the action of the symmetric group and their degrees at most $d