We give a definition of Seidel's 'relative Fukaya category', for a smooth complex projective variety, under a semipositivity assumption. We use the Cieliebak-Mohnke approach to transversality via stabilizing divisors. Two features of our construction are noteworthy: that we work relative to a normal crossings divisor that supports an effective ample divisor but need not have ample components; and that our relative Fukaya category is linear over a certain ring of multivariate power series with integer coefficients.2 Curved filtered A ∞ categories
DefinitionAll of our rings will be unital. In this section we will work over K, which will be a commutative ring equipped with an exhaustive, complete, decreasing filtration F ≥• K.One key example of such a ring K will be Z[[NE]], equipped with the m-adic filtration. The other key class of examples will be the Novikov-type rings Λ k,K defined in the Introduction.We will regularly pass from K to its associated graded ring Gr * K; for instance, from ZDefinition 2.1 A curved filtered K-linear A ∞ algebra is a Z/2-graded K-module A, equipped with an exhaustive, complete, decreasing filtration F ≥• , compatible with the module structure in the sense thatThis comes with K-linear A ∞ operationsfor all k ≥ 0, of degree 2 − k. These are required to respect the filtration in the sense thatfurthermore have µ 0 ∈ F ≥1 A, and satisfy the curved A ∞ equations.Associated to a curved filtered K-linear A ∞ algebra A, there is an uncurved Z/2 ⊕ Z-graded Gr * Klinear A ∞ algebra Gr * A whose underlying Gr * K-module is the associated graded Gr * A, with the structure maps induced by those for A. The structure map µ k has degree (2 − k, 0). The notion of c(ohomological)-unitality [Sei08, Section 2a] makes sense for Gr * A, as it is uncurved. If a c-unit exists, it necessarily has degree (0, 0).
Definition 2.2We say that A is c-unital if Gr * A is.