English

Topological Complexity is a Fibrewise L-S Category

Algebraic Topology 2012-02-28 v2

Abstract

Topological complexity \TCB\TC{B} of a space BB is introduced by M. Farber to measure how much complex the space is, which is first considered on a configuration space of a motion planning of a robot arm. We also consider a stronger version \TCMB\TCM{B} of topological complexity with an additional condition: in a robot motion planning, a motion must be stasis if the initial and the terminal states are the same. Our main goal is to show the equalities \TCB=\catBb\doubleB+1\TC{B} = \catBb{\double{B}}+1 and \TCMB=\catBB\doubleB+1\TCM{B} = \catBB{\double{B}}+1, where \doubleB=B×B\double{B}=B{\times}B is a fibrewise pointed space over BB whose projection and section are given by p\doubleB=\proj2:B×BBp_{\double{B}}=\proj_{2} : B{\times}B \to B the canonical projection to the second factor and s\doubleB=ΔB:BB×Bthediagonal.Inaddition,ourmethodinstudyingfibrewiseLScategoryisabletotreatafibrewisespacewithsingularfibres.Recently,wefoundaproblemwiththeproofofTheorem1.13whichstatesthatforafibrewisewellpointedspaces_{\double{B}}=\Delta_{B} : B \to B{\times}B the diagonal. In addition, our method in studying fibrewise L-S category is able to treat a fibrewise space with singular fibres. Recently, we found a problem with the proof of Theorem 1.13 which states that for a fibrewise well-pointed space Xover over B,wehave, we have \catBB{X}=\catBbX = \catBb{X} and that for a locally finite simplicial complex BB, we have \TCB=\TCMB\TC{B} = \TCM{B}. While we still conjecture that Theorem 1.13 is true, this problem means that, at present, no proof is given to exist. Alternatively, we show the difference between two invariants \catBbX\catBb{X} and \catBBX\catBB{X} is at most 1 and the conjecture is true for some cases. We give further corrections mainly in the proof of Theorem 1.12.

Keywords

Cite

@article{arxiv.1202.5286,
  title  = {Topological Complexity is a Fibrewise L-S Category},
  author = {Norio Iwase and Michihiro Sakai},
  journal= {arXiv preprint arXiv:1202.5286},
  year   = {2012}
}

Comments

12pages original + 5pages errata

R2 v1 2026-06-21T20:24:14.051Z