A plausible conjecture states that an element of the Jacobson radical of the endomorphism ring of an abelian p-group increases the height of any non-zero element of the socle. I construct a counter-example.

We fully characterize regular Hom-Lie structures on the incidence algebra I(X, K) of a finite connected poset X over field K. prove that such structure is sum central-valued linear map annihilating Jacobson radical with composition certain inner and multiplicative automorphisms K).

It is shown that an algebra Λ can be lifted with nilpotent Jacobson radical r = r(Λ) and has a generalized matrix unit {eii}I with each ēii in the center of Λ̄ = Λ/r iff Λ is isomorphic to a generalized path algebra with weak relations. Representations of the generalized path algebras are given. As a corollary, Λ is a finite algebra with non-zero unity element over perfect field k (e.g. a field ...