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Department of Mathematics Seminars and Talks

 
Seminar

Symplectic

Talk Information
Title
Symplectic embeddings of balls in $\mathbb{C}P^2$ and the generalized configuration space
Start date and time
15:10 on Monday November 24, 2025
Duration in minutes
50 (until 16:00 on Monday November 24, 2025)
Room
BA6183, Bahen Center, 40 St. George St.
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Abstract

Let $\mathrm{Emb}(B^4(c),\mathbb{C}P^2)$ denote the space of unparameterized symplectic embeddings of $k$ balls of capacities $(c_1,\ldots,c_k)$, 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 $\mathrm{Emb}(B^4(c),\mathbb{C}P^2)$ depends solely on the stability chambers. Based on recent results of M. Entov and M. Verbitsky on Kähler-type embeddings, we show that for $1\le k\le 8$, $\mathrm{Emb}(B^4(c),\mathbb{C}P^2)$ 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 Kähler type embeddings to a generalized version of the configuration space that incorporates both configurations of points and compatible complex structures on $\mathbb{C}P^2$.

Speaker Information
Full Name
Siyuan Yu
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Institution
University of Western Ontario
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