Introduction to Proofs

An introductory course designed to teach the fundamental concepts and techniques of mathematical proofs.

Basic Concepts

What is a Mathematical Proof?

Understanding Proofs

A mathematical proof is a logical argument that demonstrates the truth of a mathematical statement, step by step, using accepted facts and reasoning. Proofs are the backbone of mathematics—they are how mathematicians know something is true, not just believe it.

Why Proofs Matter

Proofs build trust and reliability in mathematics. Instead of guessing or checking endless examples, a proof confirms a statement for all possible cases, forever!

Types of Reasoning

  • Deductive reasoning: Uses general rules to arrive at specific conclusions.
  • Inductive reasoning: Looks for patterns from specific examples but doesn't prove statements for all cases.

Building Blocks of Proofs

  • Axioms: Basic statements assumed to be true.
  • Definitions: Precise meanings of terms.
  • Theorems: Statements proved to be true.
  • Lemmas/Corollaries: Supporting or related results.

Structure of a Proof

  1. State what you're proving.
  2. List what you know (definitions, axioms).
  3. Use logical steps to connect your facts.
  4. Arrive at the conclusion.

Try It Yourself

Proving something (even something simple!) helps you understand the logic behind mathematics and sharpens your thinking skills.

Examples

  • Proving that the sum of two even numbers is always even.

  • Showing that 2 + 2 = 4 using the definition of addition.

In a Nutshell

A proof is a logical argument that shows a mathematical statement is always true.

Key Terms

Proof
A logical argument that establishes the truth of a mathematical statement.
Axiom
A basic statement assumed to be true without proof.
Theorem
A statement that has been proven to be true.