UWO Mathematics Calendar

Week of November 09, 2025
Wednesday, November 12

Geometry and Topology

Time: 15:30
Room: MC 107
Speaker: Siyuan Yu (Western)
Title: Symplectic embeddings of balls in $\mathbb{C}P^2$ and the generalized configuration space

\textbf{Abstract.} Let \(\mathrm{IEmb}\!\big(B^{4}(c),\mathbb{C}P^{2}\big)\) denote the space of unparameterized symplectic embeddings of \(k\) balls of capacities \((c_{1},\dots,c_{k})\), where \(1\le k\le 8\). It is known from the work of S.~Anjos, J.~Li, T.-J.~Li, and M.~Pinsonnault that the space of capacities decomposes into convex polygons called stability chambers, and that the homotopy type of \(\mathrm{IEmb}\!\big(B^{4}(c),\mathbb{C}P^{2}\big)\) depends solely on the stability chambers. Based on recent results of M.~Entov and M.~Verbitsky on Kähler-type embeddings, we show that for \(1\le k\le 8\), \(\mathrm{IEmb}\!\big(B^{4}(c),\mathbb{C}P^{2}\big)\) is homotopy equivalent to a union of strata \(F_{I}\) of the configuration space of the complex projective plane \(F(\mathbb{C}P^{2},k)\). The proof relies on constructing an explicit map from the space of K\"ahler-type embeddings to a generalized version of the configuration space that incorporates both configurations of points and compatible complex structures on \(\mathbb{C}P^{2}\).

 
Friday, November 14

Transformation Groups Seminar

Time: 09:30
Room: MC 106
Speaker: Kumar Shukla (Western)
Title: Syzygies in Equivariant Cohomology of Toric Varieties

We will study the syzygy order of equivariant cohomology of toric varieties by the means of regular sequences on the piecewise polynomial algebra associated to the underlying fan.