We prove a formula expressing the motivic integral ([LS]) of a K3 surface over C((t)) with semi-stable reduction in terms of the associated limit mixed Hodge structure. Secondly, for every smooth variety over a complete discrete valuation field we define an analogue of the monodromy pairing, constructed by Grothendieck in the case of Abelian varieties, and prove that our monodromy pairing is a birational invariant of the variety. Finally, we propose a conjectural formula for the motivic integral of maximally degenerate K3 surfaces over an arbitrary complete discrete valuation field and prove this conjecture for Kummer K3 surfaces.
Preliminaries.2.1. Clemens Polytope and nerve of a strictly semi-stable scheme. Let R be a complete discrete valuation ring with residue field k and fraction field K. Recall that a scheme X of finite type over spec R is strictly semi-stable if every point x ∈ X has a Zariski neighborhood x ∈ U ⊂ X such that the morphism U → spec R factors through anétale morphismfor a uniformizer t of K. If k is perfect, X is a strictly semi-stable scheme if and only if it is regular and flat over R, the generic fiber X = X × R K is smooth over K and the special fiber Y = X × R k is a reduced strictly normal crossing divisor on X.2 There is an extensive literature on maximally degenerate Calabi-Yau varieties over C((t)). See e.g.[Mo1], [LTY].