In this short note, we complete a proof of Bergman's centralizer theorem for the free associative algebra using generic matrices approach based on our previous work [1].
IntroductionLet k be a field and k Z := k z 1 , . . . , z s be the free associative algebra over a field k with non-commuting variables in Z. G. Bergman proves in [2] that the centralizer C of a non-scalar element f in k Z is isomorphic to k[t], the ring of polynomials in one indeterminate over k.Up to our knowledge, there, no new proofs has been appeared after Bergman [2] for almost fifty years. We are using a method of deformation quantization presented by M. Kontsevich to give an alternative proof of Bergman's centralizer theorem. In our previous works [1,4], we got that the centralizer is a commutative domain of transcendence degree one.The claim in the abstract of our previous paper [1] was quite imprecise, because it just reproves and claims a part of Bergman's centralizer theorem that, the centralizer C is a commutative domain of transcendence degree one. For us, it was the most interesting part of the proof of the Bergman's centralizer theorem.However, L.Makar-Limanov notified us (and we are gratefull to him) few weeks ago that by opinion of specialists the other part is of much more importance and