Cancellation of a critical pair in discrete Morse theory and its effect on (co)boundary operators

Fuente: arXiv
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Auteurs principaux: Mondal, Anupam, Mukherjee, Sajal, Pramanik, Pritam Chandra
Format: Preprint
Publié: 2025
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author Mondal, Anupam
Mukherjee, Sajal
Pramanik, Pritam Chandra
author_facet Mondal, Anupam
Mukherjee, Sajal
Pramanik, Pritam Chandra
contents Discrete Morse theory helps us compute the homology groups of simplicial complexes in an efficient manner. A "good" gradient vector field reduces the number of critical simplices, simplifying the homology calculations by reducing them to the computation of homology groups of a simpler chain complex. This homology computation hinges on an efficient enumeration of gradient trajectories. The technique of cancelling pairs of critical simplices reduces the number of critical simplices, though it also perturbs the gradient trajectories. In this article, in a purely combinatorial manner, we derive an explicit formula for computing the modified boundary operators after cancelling a critical pair, in terms of the original boundary operators. The same formula can be obtained through a sequence of elementary row operations on the original boundary operators. Thus, it eliminates the need of enumeration of the new gradient trajectories. We also obtain a similar result for coboundary operators.
format Preprint
id arxiv_https___arxiv_org_abs_2502_06520
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cancellation of a critical pair in discrete Morse theory and its effect on (co)boundary operators
Mondal, Anupam
Mukherjee, Sajal
Pramanik, Pritam Chandra
Combinatorics
Algebraic Topology
Rings and Algebras
57Q70 (primary), 05E45, 55U15
Discrete Morse theory helps us compute the homology groups of simplicial complexes in an efficient manner. A "good" gradient vector field reduces the number of critical simplices, simplifying the homology calculations by reducing them to the computation of homology groups of a simpler chain complex. This homology computation hinges on an efficient enumeration of gradient trajectories. The technique of cancelling pairs of critical simplices reduces the number of critical simplices, though it also perturbs the gradient trajectories. In this article, in a purely combinatorial manner, we derive an explicit formula for computing the modified boundary operators after cancelling a critical pair, in terms of the original boundary operators. The same formula can be obtained through a sequence of elementary row operations on the original boundary operators. Thus, it eliminates the need of enumeration of the new gradient trajectories. We also obtain a similar result for coboundary operators.
title Cancellation of a critical pair in discrete Morse theory and its effect on (co)boundary operators
topic Combinatorics
Algebraic Topology
Rings and Algebras
57Q70 (primary), 05E45, 55U15
url https://arxiv.org/abs/2502.06520