Symmetric $(σ,τ)$-algebras and $(σ,τ)$-Hochschild cohomology
On an associative algebra, we introduce the concept of symmetric $(σ,τ)$-derivations together with a regularity condition and prove that strongly regular symmetric $(σ,τ)$-derivations are inner. Symmetric $(σ,τ)$-derivations are $(σ,τ)$-derivations that are simultaneously $(σ,τ)$-derivations as well as $(τ,σ)$-derivations, generalizing a property of commutative algebras. Motivated by this notion, we explore the geometry of symmetric $(σ,τ)$-algebras and prove that there exist a unique strongly regular symmetric $(σ,τ)$-connection. Furthermore, we introduce $(σ,τ)$-Hochschild cohomology and show that, in first degree, it describes the outer $(σ,τ)$-derivations on an associative algebra. Along the way, examples are provided to illustrate the novel concepts.