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Proof

Mathematical proof is a rigorous argument that establishes the truth of a statement beyond any doubt. Learning to read and write proofs is central to all advanced mathematics.

Key Topics

  • Direct Proof — assuming premises and deriving the conclusion step by step
  • Proof by Contradiction — assuming the negation and reaching a contradiction
  • Proof by Contrapositive — proving the contrapositive of an implication
  • Mathematical Induction — base case + inductive step for statements over natural numbers
  • Strong Induction — using all preceding cases in the inductive step
  • Proof by Cases — exhaustively covering all possibilities
  • Existence & Uniqueness Proofs — constructive and non-constructive approaches
  • Diagonalization — Cantor’s technique for uncountability and beyond