No-Go Theorems and Quantum Information TheoryThere are several theorems that are the “no-go” type within quantum information theory. The “no-broadcast” theorem extends this to mixed quantum states, or combinations of pure quantum states. No Free Lunch Theorem and Machine LearningThe “no free lunch” theorem in machine learning implies something similar. However, since the foods offered were high in salt, customers would generally buy several drinks, so the “free” lunch wasn’t really free.The “no free lunch” theorem in machine learning implies something similar. No-Hair Theorem and Black Holes The “no-hair” theorem states that all black holes can be characterized by only three externally observable parameters: mass, electric charge, and angular momentum.