文摘
Let \(A\) be a finite-dimensional algebra over an algebraically closed field \(k\). Assume \(A\) is basic and connected with \(n\) pairwise non-isomorphic simple modules. We consider the Coxeter transformation \(\phi _A\) as the automorphism of the Grothendieck group \(K_0(A)\) induced by the Auslander–Reiten translation \(\tau \) in the derived category \(\mathrm{Der}(\mathrm{mod}_A)\) of the module category \(\mathrm{mod}_A\) of finite-dimensional left \(A\)-modules. We say that \(A\) is an algebra of cyclotomic type if the characteristic polynomial \(\chi _A\) of \(\phi _A\) is a product of cyclotomic polynomials. In this paper we consider algebras of the form \(A\otimes B\) and the Mahler measure of their Coxeter polynomials. We show $$\begin{aligned} M(\chi _A)\,M(\chi _B) \le M(\chi _{A\otimes B}) \le M(\chi _A)^{r(B)+1} \, M(\chi _B)^{r(A)+1}, \end{aligned}$$