1826 – 1866
Bernhard Riemann (1826–1866) was a German mathematician whose work fundamentally transformed geometry, analysis, and the philosophy of space. His 1854 habilitation lecture introduced a generalized conception of curved space that freed geometry from Euclidean assumptions, directly enabling Einstein's general relativity. He also made foundational contributions to complex analysis, number theory, and the theory of integration.
Founded Riemannian geometry, establishing the mathematical framework for curved manifolds and non-Euclidean space
Introduced the Riemann integral, giving a rigorous foundation for integration in analysis
Proposed the Riemann Hypothesis, the still-unproven conjecture about the distribution of prime numbers
Proved the Riemann rearrangement theorem, showing conditionally convergent series can sum to any real number under reordering
Advanced the philosophical view that spatial geometry is empirical, not a priori, anticipating later developments in philosophy of physics
Reichenbach was not able to recognize the Weyl method as other than an equivalent account of empirical determination of the metric
claimMetric geometry is neither true nor false.
claimFor any real number x, the terms of a conditionally convergent series can be rearranged so that x is the sum of the rearranged series.