Let \(f:\mathbb {R}\to \mathbb {C}\) be Lebesgue measurable. Assume that \(f\) is invariant under translations by rational numbers. Show that \(f\) is constant Lebesgue almost everywhere.
Question
Math 6210 • Real Analysis
Fall 2023 • Question 2
Question
Fall 2023 • Question 2
Let \(f:\mathbb {R}\to \mathbb {C}\) be Lebesgue measurable. Assume that \(f\) is invariant under translations by rational numbers. Show that \(f\) is constant Lebesgue almost everywhere.