Measure-preserving (X, Σ, μ, T) where every T-invariant set A (i.e., T⁻¹(A) = A) has μ(A) ∈ {0, 1}. Equivalent to: the only T-invariant L² functions are constants a.e.
Measure-preserving (X, Σ, μ, T) where every T-invariant set A (i.e., T⁻¹(A) = A) has μ(A) ∈ {0, 1}. Equivalent to: the only T-invariant L² functions are constants a.e.