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Main Author: Fonseca, Renato M.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.14390
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author Fonseca, Renato M.
author_facet Fonseca, Renato M.
contents Computations with tensors are ubiquitous in fundamental physics, and so is the usage of Einstein's dummy index convention for the contraction of indices. For instance, $T_{ia}U_{aj}$ is readily recognized as the same as $T_{ib}U_{bj}$, but a computer does not know that T[i,a]U[a,j] is equal to T[i,b]U[b,j]. Furthermore, tensors may have symmetries which can be used to simply expressions: if $U_{ij}$ is antisymmetric, then $αT_{ia}U_{aj}+βT_{ib}U_{jb}=\left(α-β\right)T_{ia}U_{aj}$. The fact that tensors can have elaborate symmetries, together with the problem of dummy indices, makes it complicated to simplify polynomial expressions with tensors. In this work I will present an algorithm for doing so, which was implemented in the Mathematica package SimTeEx (Simplify Tensor Expressions). It can handle any kind of tensor symmetry.
format Preprint
id arxiv_https___arxiv_org_abs_2412_14390
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Using SimTeEx to simplify polynomial expressions with tensors
Fonseca, Renato M.
High Energy Physics - Phenomenology
Symbolic Computation
General Relativity and Quantum Cosmology
High Energy Physics - Theory
Computations with tensors are ubiquitous in fundamental physics, and so is the usage of Einstein's dummy index convention for the contraction of indices. For instance, $T_{ia}U_{aj}$ is readily recognized as the same as $T_{ib}U_{bj}$, but a computer does not know that T[i,a]U[a,j] is equal to T[i,b]U[b,j]. Furthermore, tensors may have symmetries which can be used to simply expressions: if $U_{ij}$ is antisymmetric, then $αT_{ia}U_{aj}+βT_{ib}U_{jb}=\left(α-β\right)T_{ia}U_{aj}$. The fact that tensors can have elaborate symmetries, together with the problem of dummy indices, makes it complicated to simplify polynomial expressions with tensors. In this work I will present an algorithm for doing so, which was implemented in the Mathematica package SimTeEx (Simplify Tensor Expressions). It can handle any kind of tensor symmetry.
title Using SimTeEx to simplify polynomial expressions with tensors
topic High Energy Physics - Phenomenology
Symbolic Computation
General Relativity and Quantum Cosmology
High Energy Physics - Theory
url https://arxiv.org/abs/2412.14390