,
Abhishek Rathod
,
Jonathan Spreer
Creative Commons Attribution 3.0 Unported license
Deciding whether two simplicial complexes are homotopy equivalent is a fundamental problem in topology, which is famously undecidable. There exists a combinatorial refinement of this concept, called simple-homotopy equivalence: two simplicial complexes are of the same simple-homotopy type if they can be transformed into each other by a sequence of two basic homotopy equivalences, an elementary collapse and its inverse, an elementary expansion. In this article we consider the following related problem: given a 2-dimensional simplicial complex, is there a simple-homotopy equivalence to a 1-dimensional simplicial complex using at most p expansions? We show that the problem, which we call the erasability expansion height, is W[P]-complete in the natural parameter p.
@InProceedings{bauer_et_al:LIPIcs.ESA.2019.13,
author = {Bauer, Ulrich and Rathod, Abhishek and Spreer, Jonathan},
title = {{Parametrized Complexity of Expansion Height}},
booktitle = {27th Annual European Symposium on Algorithms (ESA 2019)},
pages = {13:1--13:15},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-124-5},
ISSN = {1868-8969},
year = {2019},
volume = {144},
editor = {Bender, Michael A. and Svensson, Ola and Herman, Grzegorz},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2019.13},
URN = {urn:nbn:de:0030-drops-111346},
doi = {10.4230/LIPIcs.ESA.2019.13},
annote = {Keywords: Simple-homotopy theory, simple-homotopy type, parametrized complexity theory, simplicial complexes, (modified) dunce hat}
}