UWO Mathematics Calendar

Week of May 10, 2026
Monday, May 11

Geometry and Combinatorics

Time: 15:30
Room: MC 108
Speaker: Anton Dochtermann (Texas State University)
Title: TBA

 
Wednesday, May 13

Geometry and Topology

Time: 14:00
Room: MC 107
Speaker: Alex Suciu (Northeastern University)
Title: Koszul linearization and invariants of non-formal cdga models

I will present a method for computing resonance varieties, Alexander invariants, and Chen ranks of spaces that are not formal but admit finite-type cdga models. The method is based on Koszul linearization, which replaces the classical algebraic constructions underlying Alexander-type invariants with functorial algebraic objects built directly from the cdga, thereby shifting the role of the cohomology ring to the full model.

A key feature of this approach is the existence of functorial spectral sequences that interpolate between invariants computed from cohomology and those arising from the cdga model, with higher differentials encoding iterated Massey products. This framework yields extensions of several results from the formal setting, including the fact that cohomology controls the first-order behavior at the origin of the resonance varieties, as well as explicit formulas for infinitesimal Alexander invariants and Chen ranks in terms of the model. Discrepancies between cohomological and model-theoretic invariants thus provide computable obstructions to formality.

The constructions are functorial with respect to cdga morphisms and provide effective tools for computation. Applications include nilpotent Lie algebras and elliptic configuration spaces, as well as consequences for detecting non-formality.

 

Geometry and Topology

Time: 15:30
Room: MC 107
Speaker: Anton Dochtermann (Texas State University)
Title: TBA