A counterexample to the stochastic version of the Brouwer fixed point theorem

It is shown that the stochastic counterpart of the classical fixed point theorem for continuous maps in a finite dimensional Euclidean space (“Brouwer's theorem”) is not, in general, true. This result implies, in particular, that a careful choice of invariant sets in the stochastic version of Brouwer's theorem is necessary in the theory of stochastic nonlinear operators.