  The paper is devoted to model-theoretic properties of Kac-Moody groups with
the focus on elementary equivalence of Kac-Moody groups. We show that
elementary equivalence of (untwisted) affine Kac-Moody groups implies
coincidence of their generalized Cartan matrices and the elementary equivalence
of their ground fields. We also show that elementary equivalence of arbitrary
Kac-Moody groups over finite fields implies coincidence of these fields and an
isomorphism of their twin root data. The similar result is established for
Kac-Moody groups defined over infinite subfields of the algebraic closures of
finite fields.
