We define a new class of symplectic objects called 'stops', which, roughly speaking, are Liouville hypersurfaces in the boundary of a Liouville domain. Locally, these can be viewed as pages of a compatible open book. To a Liouville domain with a collection of disjoint stops, we assign an A∞-category called its partially wrapped Fukaya category. An exact Landau-Ginzburg model gives rise to a stop, and the corresponding partially wrapped Fukaya category is meant to agree with the Fukaya category one is supposed to assign to the Landau-Ginzburg model. As evidence, we prove a formula that relates these partially wrapped Fukaya categories to the wrapped Fukaya category of the underlying Liouville domain. This operation is mirror to removing a divisor.
373is the open-closed map. Here, the action filtration on Hochschild homology is induced from the action filtration on Floer cochain groups; for a precise definition, see Section 4.3.In particular, any punctured Riemann surface other than C and any cotangent bundle is strongly nondegenerate.Remark 1.1. A nondegenerate Liouville domain F is one for which some element e ∈ HH * (W(F )) satisfies OC(e) = 1. This condition is Abouzaid's generation criterion [2], which says that such an F admits a finite collection of Lagrangians which split-generate W(F ). Ganatra further proved that in this case, OC is an isomorphism [15], which in particular implies that e is unique.An approximate version of Theorem 4.21 can be stated as follows: Theorem 1.2. Let M be a Liouville domain, and let σ be a strongly nondegenerate stop in M . Let B ⊂ W σ (M ) be the full subcategory of objects supported near σ. Then the inclusion W σ (M ) → W(M ) induces a fully faithful functorwhere the quotient is a quotient of an A ∞ category by a full subcategory in the sense of .At the most basic level, Theorem 1.2 shows that the partially wrapped Fukaya category, together with B, really knows at least as much as the wrapped Fukaya category. That is, restricting to the zero-filtered part but remembering the stop does not lose information. At an intuitive level, this happens because the 'nice' presentation of W(M ) giving rise to the stop filtration uses a contact form with a large number of canceling Reeb chords. These chords live at different levels in the filtration, so passing to the zero-filtered part results in them no longer canceling. In a more minimal presentation, these chords could be eliminated geometrically.The key ingredient of the proof of Theorem 1.2 is an auxiliary filtration on W(M ), presented as the trivial quotient A = W(M )/B. The benefit of this quotient presentation is that it naturally contains the category A 0 = W σ (M )/B(σ) as the minimally filtered part, which makes it possible to build a homotopy which retracts A onto A 0 . The homotopy itself requires a filtered version of the annulus trick, which was introduced in [2] and extended in a forthcoming paper by Abouzaid and Auroux. Specifically, one factors the identity operation as a composition of a product and a coproduct, where ...