What is a mathematical proof?

Definition

A proof explains why a mathematical conclusion follows rather than merely showing that it works in selected examples. Its validity depends on the assumptions, definitions and logical steps used. A formal proof expresses those steps in a language suitable for precise checking.

A valid proof of one statement does not automatically establish a stronger or differently formulated claim. Its significance and the suitability of its assumptions remain separate questions. This distinction matters when evaluating model-generated mathematical results.

ELI5

Trying many examples can suggest that a rule is true. A proof explains why the rule must hold under its stated conditions, including cases nobody has individually tried.

For example, an even number of objects can be arranged in pairs. Combining two collections of pairs still leaves everything paired, explaining why adding two even numbers gives another even number.

Is checking many examples a proof?

Not generally. Examples can support a conjecture, but a proof must establish the stated claim under its assumptions.

Does a checked proof establish every related claim?

No. It establishes the exact statement proved, which may be narrower than another claim people associate with it.

  1. A flat open-book illustration with a check cutout above the blue-and-white headline PROOF IS NOT UNDERSTANDING on black.
  2. Károly Zsolnai-Fehér wearing glasses and a blue top on the left beside the blue and white headline PROOFS NEED REVIEW against black.
  3. Wes Roth against a black background beside the blue-and-white headline “AI MATH VERIFIED?”.
  4. Ellie Sleightholm points beside the blue-and-white headline '67.25% IS NOT PROOF' and a thin blue vertical line with dots on black.
  5. A flat document outline and blue check mark beside the blue and white headline AI Math Proof or Hype? on black.
  6. Pierce Freeman, Richard Diehl Martinez and Steven Kivelson appear beside the blue and white headline Proofs Need Fidelity on black.
  7. Brian Keating on the left and Terence Tao on the right, with blue and white text reading “Check AI’s math” on black.
  8. Wes Roth in blue gestures beside the blue and white "ALIEN MATH" headline against black.
  9. Nathaniel Whittemore in a blue top beside the blue and white headline Proofs Need Checking on a black background.
  10. Curt Jaimungal and Jonathan Gorard against black beside the headline “VERIFY AI PHYSICS”, with AI in blue and the other words in white.
Definition card for mathematical proof: What is a mathematical proof?

A mathematical proof is a logical argument establishing a statement from specified assumptions and accepted inference rules.