A geometric approach to equivariant factorization homology and nonabelian Poincaré duality

Abstract: Fix a finite group G and an n-dimensional orthogonal G-representation V. We define the equivariant factorization homology of a V-framed smooth G-manifold with coefficients in an $E_V$-algebra using a two-sided bar construction, generalizing [And10, KM18]. This construction uses minimal categorical background and aims for maximal concreteness, allowing convenient proofs of key properties, including invariance of equivariant factorization homology under change of tangential structures. Using a geometrically-seen scanning map, we prove an equivariant version (eNPD) of the nonabelian Poincare duality theorem due to several authors. The eNPD states that the scanning map gives a G-equivalence from the equivariant factorization homology to mapping spaces out the one-point compactification of the G-manifolds when the coefficients are G-connected. For non-G-connected coefficients, when the G-manifolds have suitable copies of R in them, the scanning map gives group completions. This generalizes the recognition principle for V -fold loops spaces in [GM17].