Authors: P. KERSTEN, I. KRASIL'SHCHIK, A. VERBOVETSKY

Using the result by D.Gessler (Differential Geom. Appl. 7 (1997) 303-324, DIPS-9/98, we show that any invariant variational bivector (resp., variational 2-form) on an evolution equation with nondegenerate right-hand side is Hamiltonian (resp., symplectic).

5 pages, AMS-LaTeX.

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