$A_{\infty}$-algebra Structures Associated to $\mathcal{K}_2$-algebras

Abstract

The notion of a $\mathcal{K}_2$-algebra was recently introduced by Cassidy and Shelton as a generalization of the notion of a Koszul algebra. The Yoneda algebra of any connected graded algebra admits a canonical $A_{\infty}$-algebra structure. This structure is trivial if the algebra is Koszul. We study the $A_{\infty}$-structure on the Yoneda algebra of a $\mathcal{K}_2$-algebra. For each non-negative integer $n$ we prove the existence of a $\mathcal{K}_2$-algebra $B$ and a canonical $A_{\infty}$-algebra structure on the Yoneda algebra of $B$ such that the higher multiplications $m_i$ are nonzero for all $3 \leq i \leq n+3$. We also provide examples which show that the $\mathcal{K}_2$ property is not detected by any obvious vanishing patterns among higher multiplications.