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∞ Real Analysis

Based on Jiří Lebl, "Basic Analysis I", licensed CC BY-SA 4.0.

The rigorous foundation beneath calculus: limits, continuity, convergence, and integration, built from the axioms of the real numbers. Translated into runnable code with diagrams.

c f(c) c-δ c+δ f(c)+ε f(c)-ε For every ε, there exists δ. That is continuity.
Chapter
1. Real Numbers The axioms, completeness, supremum, and why the rationals aren't enough
2. Sequences Convergence, monotone sequences, Bolzano-Weierstrass, and Cauchy completeness
3. Series When infinite sums converge: comparison, ratio, root tests, and power series
4. Continuous Functions Epsilon-delta continuity, IVT, EVT, and uniform continuity
5. The Derivative Definition, chain rule, mean value theorem, L'Hopital, and Taylor's theorem
6. The Riemann Integral Partitions, upper/lower sums, integrability, and the fundamental theorem
7. Sequences of Functions Pointwise vs uniform convergence, interchange of limits, Weierstrass M-test
8. Metric Spaces Open/closed sets, compactness, connectedness, and completeness in the abstract

📺 Video lectures: MIT 18.100B Real Analysis

Neighbors
  • ∫ Calculus — real analysis proves what calculus does
  • ✎ Proofs — epsilon-delta arguments are the proof technique here
  • 🎰 Probability — measure theory extends real analysis to probability
  • △ Geometry — metric spaces appear in both real analysis and geometry