Mathematical Expeditions

1 Geometry: The Parallel Postulate.- 1.1 Introduction.- 1.2 Euclid’s Parallel Postulate.- 1.3 Legendre’s Attempts to Prove the Parallel Postulate.- 1.4 Lobachevskian Geometry.- 1.5 Poincaré’s Euclidean Model for Non-Euclidean Geometry..- 2 Set Theory: Taming the Infinite.- 2.1 Introduction.- 2.2 Bolzano’s Paradoxes of the Infinite.- 2.3 Cantor’s Infinite Numbers.- 2.4 Zermelo’s Axiomatization.- 3 Analysis: Calculating Areas and Volumes.- 3.1 Introduction.- 3.2 Archimedes’ Quadrature of the Parabola.- 3.3 Archimedes’ Method.- 3.4 Cavalieri Calculates Areas of Higher Parabolas.- 3.5 Leibniz’s Fundamental Theorem of Calculus.- 3.6 Cauchy’s Rigorization of Calculus.- 3.7 Robinson Resurrects Infinitesimals.- 3.8 Appendix on Infinite Series.- 4 Number Theory: Fermat’s Last Theorem.- 4.1 Introduction.- 4.2 Euclid’s Classification of Pythagorean Triples.- 4.3 Euler’s Solution for Exponent Four.- 4.4 Germain’s General Approach.- 4.5 Kummer and the Dawn of Algebraic Number Theory.- 4.6 Appendix on Congruences.- 5 Algebra: The Search for an Elusive Formula.- 5.1 Introduction.- 5.2 Euclid’s Application of Areas and Quadratic Equations.- 5.3 Cardano’s Solution of the Cubic.- 5.4 Lagrange’s Theory of Equations.- 5.5 Galois Ends the Story.- References.- Credits.