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cs.SC2023
Factorization and root-finding for polynomials over division quaternion algebras
Przemysław Koprowski
Polynomial factorization and root finding are among the most standard themes of computational mathematics. Yet still, little has been done for polynomials over quaternion algebras,…
cs.SC2023
Pourchet's theorem in action: decomposing univariate nonnegative polynomials as sums of five squares
Victor Magron, Przemysław Koprowski, Tristan Vaccon
Pourchet proved in 1971 that every nonnegative univariate polynomial with rational coefficients is a sum of five or fewer squares. Nonetheless, there are no known algorithms for co…
cs.SC2023
Computing square roots in quaternion algebras
Przemysław Koprowski
We present an explicit algorithmic method for computing square roots in quaternion algebras over global fields of characteristic different from 2.