  We prove that geometric intersections between Weinstein handles induce
algebraic relations in the wrapped Fukaya category, which we use to study the
Grothendieck group. We produce a surjective map from middle-dimensional
singular cohomology to the Grothendieck group, show that the geometric
acceleration map to symplectic cohomology factors through the categorical
Dennis trace map, and introduce a Viterbo functor for $C^0$-close Weinstein
hypersurfaces, which gives an obstruction for Legendrians to be $C^0$-close. We
show that symplectic flexibility is a geometric manifestation of Thomason's
correspondence between split-generating subcategories and subgroups of the
Grothendieck group, which we use to upgrade Abouzaid's split-generation
criterion to a generation criterion for Weinstein domains. Thomason's theorem
produces exotic presentations for certain categories and we give geometric
analogs: exotic Weinstein presentations for standard cotangent bundles and
Legendrians whose Chekanov-Eliashberg algebras are not quasi-isomorphic but are
derived Morita equivalent.
