%0 Journal Article %T T-entropy and Variational principle for the spectral radius of weighted shift operators %A V. I. Bakhtin %J Mathematics %D 2008 %I arXiv %R 10.1017/S0143385709000716 %X In this paper we introduce a new functional invariant of discrete time dynamical systems -- the so-called t-entropy. The main result is that this t-entropy is the Legendre dual functional to the logarithm of the spectral radius of the weighted shift operator on $L^1(X,m)$ generated by the dynamical system. This result is called the Variational principle and is similar to the classical variational principle for the topological pressure. %U http://arxiv.org/abs/0809.3106v2