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This book constitutes the proceedings of the 20th International Workshop on Computer Algebra in Scientific Computing, CASC 2018, held in Lille, France, in September 2018.

The 24 full papers of this volume presented with an abstract of an invited talk and one paper corresponding to another invited talk were carefully reviewed and selected from 29 submissions. They deal with cutting-edge research in all major disciplines of computer algebra in sciences such as physics, chemistry, life sciences, and engineering.
Chapter "Positive Solutions of Systems of Signed Parametric Polynomial Inequalities" is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

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Proof-of-Work Certificates that Can Be Efficiently Computed in the Cloud (Invited Talk).- On Unimodular Matrices of Difference Operators.- Sparse Polynomial Arithmetic with the BPAS Library.- Computation of Pommaret Bases Using Syzygies.- A Strongly Consistent Finite Difference Scheme for Steady Stokes Flow and its Modified Equations.- Symbolic-Numeric Methods for Nonlinear Integro-Differential Modeling.- A Continuation Method for Visualizing Planar Real Algebraic Curves with Singularities.- From Exponential Analysis to Padé Approximation and Tensor Decomposition, in One and More Dimensions.- Symbolic Algorithm for Generating the Orthonormal Bargmann-Moshinsky Basis for SU(3) Group.- About Some Drinfel´d Associators.- On a Polytime Factorization Algorithm for Multilinear Polynomials over F 2 .- Tropical Newton-Puiseux Polynomials.- Orthogonal Tropical Linear Prevarieties.- Symbolic-Numerical Algorithms for Solving Elliptic Boundary-Value Problems Using Multivariate Simplex Lagrange Elements.- Symbolic-Numeric Simulation of Satellite Dynamics with Aerodynamic Attitude Control System.- Finding Multiple Solutions in Nonlinear Integer Programming with Algebraic Test-Sets.- Positive Solutions of Systems of Signed Parametric Polynomial Inequalities.- Qualitative Analysis of a Dynamical System with Irrational First Integrals.- Effective Localization Using Double Ideal Quotient and Its Implementation.- A Purely Functional Computer Algebra System Embedded in Haskell.- Splitting Permutation Representations of Finite Groups by Polynomial Algebra Methods.- Factoring Multivariate Polynomials with Many Factors and Huge Coefficients.- Beyond the First Class of Analytic Complexity.- A Theory and an Algorithm for Computing Sparse Multivariate Polynomial Remainder Sequence.- A Blackbox Polynomial System Solver on Parallel Shared Memory Computers.

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