Assume that \(u\in H^1(\mathbb {T}^n)\) is a weak solution to \(Lu=f(x)\) on \(\mathbb {T}^n\), where \(f\in C^\infty (\mathbb {T}^n)\). Show that \(u\in C^\infty (\mathbb {T}^n)\).
Question
Math 6410 • ODE
Fall 1997 • Question 20
Question
Fall 1997 • Question 20
Assume that \(u\in H^1(\mathbb {T}^n)\) is a weak solution to \(Lu=f(x)\) on \(\mathbb {T}^n\), where \(f\in C^\infty (\mathbb {T}^n)\). Show that \(u\in C^\infty (\mathbb {T}^n)\).