Every continuous map f: Dⁿ → Dⁿ (closed n-disk) has a fixed point. Proved via homology or degree theory; foundational for game theory (Nash) and economics (Arrow-Debreu).
Every continuous map f: Dⁿ → Dⁿ (closed n-disk) has a fixed point. Proved via homology or degree theory; foundational for game theory (Nash) and economics (Arrow-Debreu).