Belatedly to Simon Lyakhovich on the occasion of his 50th birthday.
AbstractWe construct a 2-colored operad Ger + ∞ which, on the one hand, extends the operad Ger ∞ governing homotopy Gerstenhaber algebras and, on the other hand, extends the 2-colored operad governing open-closed homotopy algebras (OCHA). We show that Tamarkin's Ger ∞ -structure on the Hochschild cochain complex C • (A, A) of an A ∞algebra A extends naturally to a Ger + ∞ -structure on the pair (C • (A, A), A) . We show that a formality quasi-isomorphism for the Hochschild cochains of the polynomial algebra can be obtained via transfer of this Ger + ∞ -structure to the cohomology of the pair (C • (A, A), A) . We show that Ger + ∞ is a sub DG operad of the first sheet E 1 (SC) of the homology spectral sequence for the Fulton-MacPherson version SC of Voronov's Swiss Cheese operad. Finally, we prove that the DG operads Ger + ∞ and E 1 (SC) are non-formal.