An 𝒪-operator on an
associative algebra is a generalization of a Rota–Baxter operator that plays an
important role in the Hopf algebra approach of Connes and Kreimer to the
renormalization of quantum field theory. It is also the associative analog of an
𝒪-operator on a Lie algebra in the study of the classical Yang–Baxter equation. We
introduce the concept of an extended 𝒪-operator on an associative algebra whose Lie
algebra analog has been applied to generalized Lax pairs and PostLie algebras. We
study algebraic structures coming from extended 𝒪-operators. Continuing the work
of Aguiar deriving Rota–Baxter operators from the associative Yang–Baxter
equation, we show that its solutions correspond to extended 𝒪-operators through a
duality. We also establish a relationship of extended 𝒪-operators with the generalized
associative Yang–Baxter equation.