  We introduce a class of potential submanifolds in pseudo-Euclidean spaces
(each N-dimensional potential submanifold is a special flat torsionless
submanifold in a 2N-dimensional pseudo-Euclidean space) and prove that each
N-dimensional Frobenius manifold can be locally represented as an N-dimensional
potential submanifold. We show that all potential submanifolds bear natural
special structures of Frobenius algebras on their tangent spaces. These special
Frobenius structures are generated by the corresponding flat first fundamental
form and the set of the second fundamental forms of the submanifolds (in fact,
the structural constants are given by the set of the Weingarten operators of
the submanifolds). We prove that the associativity equations of two-dimensional
topological quantum field theories are very natural reductions of the
fundamental nonlinear equations of the theory of submanifolds in
pseudo-Euclidean spaces and define locally the class of potential submanifolds.
The problem of explicit realization of an arbitrary concrete Frobenius manifold
as a potential submanifold in a pseudo-Euclidean space is reduced to solving a
linear system of second-order partial differential equations. For concrete
Frobenius manifolds, this realization problem can be solved explicitly in
elementary and special functions.
