Skorohod 1961: any centered random-variable X embeddable in BM via stopping-time tau s.t. B_tau ~= X; basis of weak-convergence proofs + Donsker invariance principle.
Skorohod 1961: any centered random-variable X embeddable in BM via stopping-time tau s.t. B_tau ~= X; basis of weak-convergence proofs + Donsker invariance principle.