Session 31. Representation Theory, Transformation Groups, and Applications

Isovariant Borsuk-Ulam type theorems and isovariant maps between representation spaces

Ikumitsu Nagasaki, Kyoto Prefectural University of Medicine, Japan
The talk is based on the joint work with Fumihiro Ushitaki (Kyoto Sangyo University)
For a compact Lie group \(G\), a \(G\)-isovariant map \(f:X\to Y\) between two \(G\)-spaces \(X\) and \(Y\) is a \(G\)-equivariant map preserving the isotropy subgroups.

In this talk, we consider isovariant maps between \(G\)-representation spaces. First, we review Wasserman's results, as well as our recent results about the isovariant Borsuk-Ulam theorem. Secondly, we consider bi-isovariant equivalent representations.

We say that two representations \(V\) and \(W\) are bi-isovariant equivalent if there exist isovariant maps from \(V\) to \(W\) and from \(W\) to \(V\). We show that if \(V\) and \(W\) are bi-isovariant, then their dimension functions coincide. Furthermore, if \(G\) is connected, these representations are isomorphic. In order to give a proof, we use tom Dieck's and Traczyk's results in representation theory.

References
  1. I. Nagasaki and F. Ushitaki New examples of the Borsuk-Ulam groups , RIMS Kokyuroku Bessatsu (2013), 109-119.
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