涩里番

Title: Odd Moebius鈥擪antor Ring Puzzles

Abstract: Moebius鈥擪antor complexes were introduced by Barr茅 and Pichot to serve as a canonical family of spaces of 鈥渋ntermediate rank鈥�, in an attempt to shed light on the flat-closing conjecture. They form a rich family of locally-defined CAT(0) spaces with interesting flat geometry, and can be distinguished up to isomorphism by an invariant called the parity. In this talk, we give an introduction to Moebius鈥擪antor complexes and report on a recent work by Barr茅, Pichot, and myself classifying the odd ring puzzles associated with them. These are tessellations of the Euclidean plane with local conditions constraining the set of admissible neighbourhoods, arising as embedded flat planes in our complexes.

We will gather for teatime in the lounge after the talk. Note that this will be the last talk of the semester.

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