EN
We prove that for the spectral radius of a weighted composition operator $aT_{α}$, acting in the space $L^{p}(X,𝓑,μ)$, the following variational principle holds:
$ln r (aT_{α}) = max_{ν ∈ M¹_{α,e}} ∫_{X} ln|a|dν$,
where X is a Hausdorff compact space, α: X → X is a continuous mapping preserving a Borel measure μ with suppμ = X, $M¹_{α,e}$ is the set of all α-invariant ergodic probability measures on X, and a: X → ℝ is a continuous and $𝓑_{∞}$-measurable function, where $𝓑_{∞}= ⋂_{n=0}^{∞} α^{-n}(𝓑)$. This considerably extends the range of validity of the above formula, which was previously known in the case when α is a homeomorphism.