Publications

2022

[Grasegger]

Flexible placements of graphs with rotational symmetry

Sean Dewar, Georg Grasegger, Jan Legerský

In: 2nd IMA Conference on Mathematics of Robotics, W. Holderbaum, J.M. Selig (ed.), Springer Proceedings in Advanced Robotics 21, pp. 89-97. 2022. 978-3-030-91351-9. [doi]
[bib]
@inproceedings{RISC6387,
author = {Sean Dewar and Georg Grasegger and Jan Legerský},
title = {{Flexible placements of graphs with rotational symmetry}},
booktitle = {{2nd IMA Conference on Mathematics of Robotics}},
language = {english},
series = {Springer Proceedings in Advanced Robotics},
volume = {21},
pages = {89--97},
isbn_issn = {978-3-030-91351-9},
year = {2022},
editor = {W. Holderbaum and J.M. Selig},
refereed = {yes},
length = {9},
url = {https://doi.org/10.1007/978-3-030-91352-6_9}
}
[Grasegger]

Zero-Sum Cycles in Flexible Non-triangular Polyhedra

Matteo Gallet, Georg Grasegger, Jan Legerský, Josef Schicho

In: 2nd IMA Conference on Mathematics of Robotics, W. Holderbaum, J.M. Selig (ed.), Springer Proceedings in Advanced Robotics 21, pp. 137-143. 2022. 978-3-030-91351-9. [doi]
[bib]
@inproceedings{RISC6388,
author = {Matteo Gallet and Georg Grasegger and Jan Legerský and Josef Schicho},
title = {{Zero-Sum Cycles in Flexible Non-triangular Polyhedra}},
booktitle = {{2nd IMA Conference on Mathematics of Robotics}},
language = {english},
series = {Springer Proceedings in Advanced Robotics},
volume = {21},
pages = {137--143},
isbn_issn = {978-3-030-91351-9},
year = {2022},
editor = {W. Holderbaum and J.M. Selig},
refereed = {yes},
length = {7},
url = {https://doi.org/10.1007/978-3-030-91352-6_14}
}

2021

[Ablinger]

Extensions of the AZ-algorithm and the Package MultiIntegrate

J. Ablinger

In: Anti-Differentiation and the Calculation of Feynman Amplitudes, J. Blümlein, C. Schneider (ed.), Texts & Monographs in Symbolic Computation (A Series of the Research Institute for Symbolic Computation, Johannes Kepler University, Linz, Austria) , pp. 35-61. 2021. Springer, ISBN 978-3-030-80218-9. arXiv:2101.11385 [cs.SC]. [doi]
[bib]
@incollection{RISC6408,
author = {J. Ablinger},
title = {{Extensions of the AZ-algorithm and the Package MultiIntegrate}},
booktitle = {{Anti-Differentiation and the Calculation of Feynman Amplitudes}},
language = {english},
abstract = {We extend the (continuous) multivariate Almkvist-Zeilberger algorithm inorder to apply it for instance to special Feynman integrals emerging in renormalizable Quantum field Theories. We will consider multidimensional integrals overhyperexponential integrals and try to find closed form representations in terms ofnested sums and products or iterated integrals. In addition, if we fail to computea closed form solution in full generality, we may succeed in computing the firstcoeffcients of the Laurent series expansions of such integrals in terms of indefnitenested sums and products or iterated integrals. In this article we present the corresponding methods and algorithms. Our Mathematica package MultiIntegrate,can be considered as an enhanced implementation of the (continuous) multivariateAlmkvist Zeilberger algorithm to compute recurrences or differential equations forhyperexponential integrands and integrals. Together with the summation packageSigma and the package HarmonicSums our package provides methods to computeclosed form representations (or coeffcients of the Laurent series expansions) of multidimensional integrals over hyperexponential integrands in terms of nested sums oriterated integrals.},
series = {Texts & Monographs in Symbolic Computation (A Series of the Research Institute for Symbolic Computation, Johannes Kepler University, Linz, Austria)},
pages = {35--61},
publisher = {Springer},
isbn_issn = {ISBN 978-3-030-80218-9},
year = {2021},
note = {arXiv:2101.11385 [cs.SC]},
editor = {J. Blümlein and C. Schneider},
refereed = {yes},
keywords = {multivariate Almkvist-Zeilberger algorithm, hyperexponential integrals, iterated integrals, nested sums},
length = {27},
url = {https://doi.org/10.1007/978-3-030-80219-6_2}
}
[Ablinger]

Extensions of the AZ-algorithm and the Package MultiIntegrate

J. Ablinger

In: Anti-Differentiation and the Calculation of Feynman Amplitudes, J. Blümlein, C. Schneider (ed.), Texts & Monographs in Symbolic Computation (A Series of the Research Institute for Symbolic Computation, Johannes Kepler University, Linz, Austria) , pp. 35-61. 2021. Springer, ISBN 978-3-030-80218-9. arXiv:2101.11385 [cs.SC]. [doi]
[bib]
@incollection{RISC6409,
author = {J. Ablinger},
title = {{Extensions of the AZ-algorithm and the Package MultiIntegrate}},
booktitle = {{Anti-Differentiation and the Calculation of Feynman Amplitudes}},
language = {english},
abstract = {We extend the (continuous) multivariate Almkvist-Zeilberger algorithm inorder to apply it for instance to special Feynman integrals emerging in renormalizable Quantum field Theories. We will consider multidimensional integrals overhyperexponential integrals and try to find closed form representations in terms ofnested sums and products or iterated integrals. In addition, if we fail to computea closed form solution in full generality, we may succeed in computing the firstcoeffcients of the Laurent series expansions of such integrals in terms of indefnitenested sums and products or iterated integrals. In this article we present the corresponding methods and algorithms. Our Mathematica package MultiIntegrate,can be considered as an enhanced implementation of the (continuous) multivariateAlmkvist Zeilberger algorithm to compute recurrences or differential equations forhyperexponential integrands and integrals. Together with the summation packageSigma and the package HarmonicSums our package provides methods to computeclosed form representations (or coeffcients of the Laurent series expansions) of multidimensional integrals over hyperexponential integrands in terms of nested sums oriterated integrals.},
series = {Texts & Monographs in Symbolic Computation (A Series of the Research Institute for Symbolic Computation, Johannes Kepler University, Linz, Austria)},
pages = {35--61},
publisher = {Springer},
isbn_issn = {ISBN 978-3-030-80218-9},
year = {2021},
note = {arXiv:2101.11385 [cs.SC]},
editor = {J. Blümlein and C. Schneider},
refereed = {yes},
keywords = {multivariate Almkvist-Zeilberger algorithm, hyperexponential integrals, iterated integrals, nested sums},
length = {27},
url = {https://doi.org/10.1007/978-3-030-80219-6_2}
}
[Cerna]

A Special Case of Schematic Syntactic Unification

David M. Cerna

CAS ICS / RISC. Technical report, 2021. [pdf]
[bib]
@techreport{RISC6349,
author = {David M. Cerna},
title = {{A Special Case of Schematic Syntactic Unification}},
language = {english},
abstract = {We present a unification problem based on first-order syntactic unification which ask whether every problemin a schematically-defined sequence of unification problems isunifiable, so called loop unification. Alternatively, our problemmay be formulated as a recursive procedure calling first-ordersyntactic unification on certain bindings occurring in the solvedform resulting from unification. Loop unification is closely relatedto Narrowing as the schematic constructions can be seen as arewrite rule applied during unification, and primal grammars, aswe deal with recursive term constructions. However, loop unifi-cation relaxes the restrictions put on variables as fresh as wellas used extra variables may be introduced by rewriting. In thiswork we consider an important special case, so called semiloopunification. We provide a sufficient condition for unifiability of theentire sequence based on the structure of a sufficiently long initialsegment. It remains an open question whether this conditionis also necessary for semiloop unification and how it may beextended to loop unification.},
year = {2021},
institution = {CAS ICS / RISC},
length = {8}
}
[Dundua]

Variadic equational matching in associative and commutative theories

Besik Dundua, Temur Kutsia, Mircea Marin

Journal of Symbolic Computation 106, pp. 78-109. 2021. Elsevier, ISSN 0747-7171. [doi] [pdf]
[bib]
@article{RISC6260,
author = {Besik Dundua and Temur Kutsia and Mircea Marin},
title = {{Variadic equational matching in associative and commutative theories}},
language = {english},
journal = {Journal of Symbolic Computation},
volume = {106},
pages = {78--109},
publisher = {Elsevier},
isbn_issn = {ISSN 0747-7171},
year = {2021},
refereed = {yes},
length = {32},
url = {https://doi.org/10.1016/j.jsc.2021.01.001}
}
[Falkensteiner]

On Initials and the Fundamental Theorem of Tropical Partial Differential Geometry

S. Falkensteiner, C. Garay-Lopez, M. Haiech, M. P. Noordman, F. Boulier, Z. Toghani

Journal of Symbolic Computation, pp. 1-22. 2021. ISSN: 0747-7171. [url]
[bib]
@article{RISC6335,
author = {S. Falkensteiner and C. Garay-Lopez and M. Haiech and M. P. Noordman and F. Boulier and Z. Toghani},
title = {{On Initials and the Fundamental Theorem of Tropical Partial Differential Geometry}},
language = {english},
journal = {Journal of Symbolic Computation},
pages = {1--22},
isbn_issn = {ISSN: 0747-7171},
year = {2021},
refereed = {yes},
keywords = {Differential Algebra, Tropical Differential Algebraic Geometry, Power Series Solutions, Newton Polyhedra, Arc Spaces, Tropical Differential Equations, Initial forms of Differential Polynomials},
length = {22},
url = {http://hal.archives-ouvertes.fr/hal-03122437v1/document}
}
[Falkensteiner]

On The Relationship Between Differential Algebra and Tropical Differential Algebraic Geometry

F. Boulier, S. Falkensteiner, M.P. Noordman, O.L. Sanchez

In: International Workshop on Computer Algebra in Scientific Computing, F. Boulier, M. England, T. Sadykov, E. Vorozhtsov (ed.), Proceedings of Computer Algebra in Scientific Computing, pp. 62-77. 2021. Springer, ISSN 0302-9743. [doi]
[bib]
@inproceedings{RISC6337,
author = {F. Boulier and S. Falkensteiner and M.P. Noordman and O.L. Sanchez},
title = {{On The Relationship Between Differential Algebra and Tropical Differential Algebraic Geometry}},
booktitle = {{International Workshop on Computer Algebra in Scientific Computing}},
language = {english},
pages = {62--77},
publisher = {Springer},
isbn_issn = {ISSN 0302-9743},
year = {2021},
editor = {F. Boulier and M. England and T. Sadykov and E. Vorozhtsov},
refereed = {yes},
length = {16},
conferencename = {Computer Algebra in Scientific Computing},
url = {https://doi.org/10.1007/978-3-030-85165-1_5}
}
[Grasegger]

Combinatorics of Bricard's octahedra

M. Gallet, G. Grasegger, J. Legerský, J. Schicho

Comptes Rendus. Mathématique 359(1), pp. 7-38. 2021. Académie des sciences, Paris, ISSN 1631-073X. [doi]
[bib]
@article{RISC6288,
author = {M. Gallet and G. Grasegger and J. Legerský and J. Schicho},
title = {{Combinatorics of Bricard's octahedra}},
language = {english},
journal = {Comptes Rendus. Mathématique},
volume = {359},
number = {1},
pages = {7--38},
publisher = {Académie des sciences, Paris},
isbn_issn = {ISSN 1631-073X},
year = {2021},
refereed = {yes},
length = {32},
url = {https://doi.org/10.5802/crmath.132}
}
[Grasegger]

On the Existence of Paradoxical Motions of Generically Rigid Graphs on the Sphere

M. Gallet, G. Grasegger, J. Legerský, J. Schicho

SIAM Journal on Discrete Mathematics 35(1), pp. 325-361. 2021. ISSN 0895-4801. [doi]
[bib]
@article{RISC6290,
author = {M. Gallet and G. Grasegger and J. Legerský and J. Schicho},
title = {{On the Existence of Paradoxical Motions of Generically Rigid Graphs on the Sphere}},
language = {english},
journal = {SIAM Journal on Discrete Mathematics},
volume = {35},
number = {1},
pages = {325--361},
isbn_issn = {ISSN 0895-4801},
year = {2021},
refereed = {yes},
length = {37},
url = {https://doi.org/10.1137/19M1289467}
}
[Grasegger]

Bracing frameworks consisting of parallelograms

Georg Grasegger, Jan Legerský

The Art of Discrete and Applied Mathematics Accepted Manuscripts, pp. --. 2021. 2590-9770. [doi]
[bib]
@article{RISC6389,
author = {Georg Grasegger and Jan Legerský},
title = {{Bracing frameworks consisting of parallelograms}},
language = {english},
journal = {The Art of Discrete and Applied Mathematics},
volume = {Accepted Manuscripts},
pages = {----},
isbn_issn = {2590-9770},
year = {2021},
refereed = {yes},
length = {0},
url = {https://doi.org/10.26493/2590-9770.1379.7a4}
}
[Hemmecke]

Construction of modular function bases for $Gamma_0(121)$ related to $p(11n+6)$

Ralf Hemmecke, Peter Paule, Silviu Radu

Integral Transforms and Special Functions 32(5-8), pp. 512-527. 2021. Taylor & Francis, 1065-2469. [doi]
[bib]
@article{RISC6342,
author = {Ralf Hemmecke and Peter Paule and Silviu Radu},
title = {{Construction of modular function bases for $Gamma_0(121)$ related to $p(11n+6)$}},
language = {english},
abstract = {Motivated by arithmetic properties of partitionnumbers $p(n)$, our goal is to find algorithmicallya Ramanujan type identity of the form$sum_{n=0}^{infty}p(11n+6)q^n=R$, where $R$ is apolynomial in products of the form$e_alpha:=prod_{n=1}^{infty}(1-q^{11^alpha n})$with $alpha=0,1,2$. To this end we multiply theleft side by an appropriate factor such the resultis a modular function for $Gamma_0(121)$ havingonly poles at infinity. It turns out thatpolynomials in the $e_alpha$ do not generate thefull space of such functions, so we were led tomodify our goal. More concretely, we give threedifferent ways to construct the space of modularfunctions for $Gamma_0(121)$ having only poles atinfinity. This in turn leads to three differentrepresentations of $R$ not solely in terms of the$e_alpha$ but, for example, by using as generatorsalso other functions like the modular invariant $j$.},
journal = {Integral Transforms and Special Functions},
volume = {32},
number = {5-8},
pages = {512--527},
publisher = {Taylor & Francis},
isbn_issn = {1065-2469},
year = {2021},
refereed = {yes},
keywords = {Ramanujan identities, bases for modular functions, integral bases},
sponsor = {FWF (SFB F50-06)},
length = {16},
url = {https://doi.org/10.1080/10652469.2020.1806261}
}
[Jebelean]

A Heuristic Prover for Elementary Analysis in Theorema

Tudor Jebelean

Technical report no. 21-07 in RISC Report Series, Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz, Austria. ISSN 2791-4267 (online). April 2021. [doi] [pdf]
[bib]
@techreport{RISC6293,
author = {Tudor Jebelean},
title = {{A Heuristic Prover for Elementary Analysis in Theorema}},
language = {english},
abstract = {We present the application of certain heuristic techniques for the automation of proofs in elementary analysis. the techniques used are: the S-decomposition method for formulae with alternating quantifiers, quantifier elimination by cylindrical algebraic decomposition, analysis of terms behavior in zero, bounding the [Epsilon]-bounds, semantic simplification of expressions involving absolute value, polynomial arithmetic, usage of equal arguments to arbitrary functions, and automatic reordering of proof steps in order to check the admisibility of solutions to the metavariables. The proofs are very similar to those produced automatically, but they are edited for readability and aspect, and also for inserting the appropriate explanation about the use of the proof techniques. The proofs are: convergence of product of two sequences, continuity of the sum of two functions, uniform continuity of the sum of two functions, uniform continuity of the product of two functions, and continuity of the composition of functions.},
number = {21-07},
year = {2021},
month = {April},
keywords = {Theorema, S-decomposition, automated theorem proving},
length = {29},
type = {RISC Report Series},
institution = {Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz},
address = {Altenberger Straße 69, 4040 Linz, Austria},
issn = {2791-4267 (online)}
}
[Jimenez Pastor]

On C2-Finite Sequences

Antonio Jiménez-Pastor, Philipp Nuspl, Veronika Pillwein

In: Proceedings of the 2021 on International Symposium on Symbolic and Algebraic Computation, Frédéric Chyzak, George Labahn (ed.), ISSAC '21 , pp. 217-224. 2021. Association for Computing Machinery, New York, NY, USA, ISBN 9781450383820. [doi]
[bib]
@inproceedings{RISC6348,
author = {Antonio Jiménez-Pastor and Philipp Nuspl and Veronika Pillwein},
title = {{On C2-Finite Sequences}},
booktitle = {{Proceedings of the 2021 on International Symposium on Symbolic and Algebraic Computation}},
language = {english},
abstract = {Holonomic sequences are widely studied as many objects interesting to mathematiciansand computer scientists are in this class. In the univariate case, these are the sequencessatisfying linear recurrences with polynomial coefficients and also referred to asD-finite sequences. A subclass are C-finite sequences satisfying a linear recurrencewith constant coefficients.We investigate the set of sequences which satisfy linearrecurrence equations with coefficients that are C-finite sequences. These sequencesare a natural generalization of holonomic sequences. In this paper, we show that C2-finitesequences form a difference ring and provide methods to compute in this ring.},
series = {ISSAC '21},
pages = {217--224},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
isbn_issn = {ISBN 9781450383820},
year = {2021},
editor = {Frédéric Chyzak and George Labahn},
refereed = {yes},
keywords = {holonomic sequences, algorithms, closure properties, difference equations},
length = {8},
url = {https://doi.org/10.1145/3452143.3465529}
}
[Jimenez Pastor]

An extension of holonomic sequences: C^2-finite sequences

Antonio Jiménez-Pastor, Philipp Nuspl, Veronika Pillwein

Technical report no. 21-20 in RISC Report Series, Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz, Austria. ISSN 2791-4267 (online). December 2021. Licensed under CC BY 4.0 International. [doi] [pdf]
[bib]
@techreport{RISC6390,
author = {Antonio Jiménez-Pastor and Philipp Nuspl and Veronika Pillwein},
title = {{An extension of holonomic sequences: C^2-finite sequences}},
language = {english},
abstract = {Holonomic sequences are widely studied as many objects interesting to mathematicians and computer scientists are in this class. In the univariate case, these are the sequences satisfying linear recurrences with polynomial coefficients and also referred to as $D$-finite sequences. A subclass are $C$-finite sequences satisfying a linear recurrence with constant coefficients.We investigate the set of sequences which satisfy linear recurrence equations with coefficients that are $C$-finite sequences. These sequences are a natural generalization of holonomic sequences. In this paper, we show that $C^2$-finite sequences form a difference ring and provide methods to compute in this ring. Furthermore, we provide an analogous construction for $D^2$-finite sequences, i.e., sequences satisfying a linear recurrence with holonomic coefficients. We show that these constructions can be iterated and obtain an increasing chain of difference rings.},
number = {21-20},
year = {2021},
month = {December},
keywords = {Difference equations, holonomic sequences, closure properties, algorithms},
length = {26},
license = {CC BY 4.0 International},
type = {RISC Report Series},
institution = {Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz},
address = {Altenberger Straße 69, 4040 Linz, Austria},
issn = {2791-4267 (online)}
}
[Jimenez Pastor]

Differentially definable functions: a survey

Jiménez-Pastor Antonio, Pillwein Veronika

In: Proceedings in Applied Mathematics and Mechanics (PAMM), Gesellschaft für Angewandte Mathematik und Mechanik (GAMM) (ed.), Proceedings of Special Issue: 91st Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM)21/1, pp. e202100178-e2021001. 2021. [doi]
[bib]
@inproceedings{RISC6410,
author = {Jiménez-Pastor Antonio and Pillwein Veronika},
title = {{Differentially definable functions: a survey}},
booktitle = {{Proceedings in Applied Mathematics and Mechanics (PAMM)}},
language = {english},
abstract = {Abstract Most widely used special functions, such as orthogonal polynomials, Bessel functions, Airy functions, etc., are defined as solutions to differential equations with polynomial coefficients. This class of functions is referred to as D-finite functions. There are many symbolic algorithms (and implementations thereof) to operate with these objects exactly. Recently, we have extended this notion to a more general class that also allows for good symbolic handling: differentially definable functions. In this paper, we give an overview on what is currently known about this new class.},
volume = {21},
number = {1},
pages = {e202100178--e2021001},
isbn_issn = {?},
year = {2021},
editor = { Gesellschaft für Angewandte Mathematik und Mechanik (GAMM)},
refereed = {yes},
length = {4},
conferencename = {Special Issue: 91st Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM)},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pamm.202100178}
}
[Kutsia]

9th International Symposium on Symbolic Computation in Software Science (SCSS 2021), short and work-in-progress papers

Temur Kutsia (editor)

Technical report no. 21-16 in RISC Report Series, Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz, Austria. ISSN 2791-4267 (online). August 2021. Licensed under CC BY 4.0 International. [doi] [pdf]
[bib]
@techreport{RISC6359,
author = {Temur Kutsia (editor)},
title = {{9th International Symposium on Symbolic Computation in Software Science (SCSS 2021), short and work-in-progress papers}},
language = {english},
abstract = {This collection contains short and work-in-progress papers presented at the 9th International Symposium on Symbolic Computation in Software Science, SCSS 2021.},
number = {21-16},
year = {2021},
month = {August},
keywords = {Symbolic computation, software science, artificial intelligence},
length = {56},
license = {CC BY 4.0 International},
type = {RISC Report Series},
institution = {Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz},
address = {Altenberger Straße 69, 4040 Linz, Austria},
issn = {2791-4267 (online)}
}
[Legersky]

On the maximal number of real embeddings of minimally rigid graphs in R2, R3 and S2

E. Bartzos, I.Z. Emiris, J. Legerský, E. Tsigaridas

Journal of Symbolic Computation 102, pp. 189-208. 2021. ISSN 0747-7171. [doi]
[bib]
@article{RISC5992,
author = {E. Bartzos and I.Z. Emiris and J. Legerský and E. Tsigaridas},
title = {{On the maximal number of real embeddings of minimally rigid graphs in R2, R3 and S2}},
language = {english},
journal = {Journal of Symbolic Computation},
volume = {102},
pages = {189--208},
isbn_issn = {ISSN 0747-7171},
year = {2021},
refereed = {yes},
length = {20},
url = {https://doi.org/10.1016/j.jsc.2019.10.015}
}
[Maletzky]

A generic and executable formalization of signature-based Gröbner basis algorithms

Alexander Maletzky

J. Symb. Comput. 106, pp. 23-47. 2021. Elsevier, ISSN 0747-7171. arXiv:2012.02239 [cs.SC], https://doi.org/10.1016/j.jsc.2020.12.001. [url]
[bib]
@article{RISC6225,
author = {Alexander Maletzky},
title = {{A generic and executable formalization of signature-based Gröbner basis algorithms}},
language = {english},
journal = {J. Symb. Comput.},
volume = {106},
pages = {23--47},
publisher = {Elsevier},
isbn_issn = {ISSN 0747-7171},
year = {2021},
note = {arXiv:2012.02239 [cs.SC], https://doi.org/10.1016/j.jsc.2020.12.001},
refereed = {yes},
length = {25},
url = {https://arxiv.org/abs/2012.02239}
}
[Mitteramskogler]

General solutions of first-order algebraic ODEs in simple constant extensions

Johann J. Mitteramskogler, Franz Winkler

Technical report no. 21-18 in RISC Report Series, Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz, Austria. ISSN 2791-4267 (online). September 2021. Licensed under CC BY 4.0 International. [doi] [pdf]
[bib]
@techreport{RISC6364,
author = {Johann J. Mitteramskogler and Franz Winkler},
title = {{General solutions of first-order algebraic ODEs in simple constant extensions}},
language = {english},
abstract = {If a first-order algebraic ODE is defined over a certain differential field, then the most elementary solution class, in which one can hope to find a general solution, is given by the adjunction of a single arbitrary constant to this field. Solutions of this type give rise to a particular kind of generic point—a rational parametrization—of an algebraic curve which is associated in a natural way to the ODE’s defining polynomial. As for the opposite direction, we show that a suitable rational parametrization of the associated curve can be extended to a general solution of the ODE if and only if one can find a certain automorphism of the solution field. These automorphisms are determined by linear rational functions, i.e. Möbius transformations. Intrinsic properties of rational parametrizations, in combination with the particular shape of such automorphisms, lead to a number of necessary conditions on the existence of general solutions in this solution class. Furthermore, the desired linear rational function can be determined by solving a simple differential system over the ODE’s field of definition. All results are derived in a purely algebraic fashion and apply to any differential field of characteristic zero with arbitrary derivative operator.},
number = {21-18},
year = {2021},
month = {September},
keywords = {Algebraic ordinary differential equation, general solution, algebraic curve, rational parametrization},
length = {17},
license = {CC BY 4.0 International},
type = {RISC Report Series},
institution = {Research Institute for Symbolic Computation (RISC), Johannes Kepler University Linz},
address = {Altenberger Straße 69, 4040 Linz, Austria},
issn = {2791-4267 (online)}
}

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