Every simple closed curve γ in the plane divides R² ∖ γ into exactly two connected components — a bounded interior and an unbounded exterior — and γ is their common boundary. Jordan 1887; rigorous proof by Veblen 1905; formal proof by…
Every simple closed curve γ in the plane divides R² ∖ γ into exactly two connected components — a bounded interior and an unbounded exterior — and γ is their common boundary. Jordan 1887; rigorous proof by Veblen 1905; formal proof by…