Masha Vlasenko 

Title: Formal groups and congruences

Abstract: 
We give a criterion of integrality of a one-parametric
formal group law in terms of congruences satisfied by the coefficients
of its logarithm. These congruences allow us to prove a p-adic
analytic formula for the characteristic polynomial of the Frobenius
endomorphism of the reduction of the group law modulo p. We will
discuss computation of p-adic unit eigenvalues of Frobenius on the
middle cohomology of Calabi-Yau hypersurfaces as an application.