  We state and prove Kuhn's equivalence theorem for a new representation of
games, the intrinsic form. First, we introduce games in intrinsic form where
information is represented by $\sigma$-fields over a product set. For this
purpose, we adapt to games the intrinsic representation that Witsenhausen
introduced in control theory. Those intrinsic games do not require an explicit
description of the play temporality, as opposed to extensive form games on
trees. Second, we prove, for this new and more general representation of games,
that behavioral and mixed strategies are equivalent under perfect recall
(Kuhn's theorem). As the intrinsic form replaces the tree structure with a
product structure, the handling of information is easier. This makes the
intrinsic form a new valuable tool for the analysis of games with information.
