🔬 Discovery

Cauchy–Riemann equations

Ecuaciones de Cauchy-Riemann

Date
1752 · confidence high
Place
Paris, France
Credited to
Jean le Rond d'Alembert
Field
Knowledge & symbols

⚠️ Disputed: the sources disagree.

What was discovered

D'Alembert introduced these equations in his essay on fluid resistance, decades before Cauchy and Riemann turned them into a cornerstone of complex analysis: they are the condition a function must satisfy to be complex-differentiable.

Despite bearing the names of Cauchy and Riemann, d'Alembert had already written them down in 1752 and Euler connected them to analytic functions in 1797; Cauchy (1814) and Riemann (1851) built the modern theory of complex functions on them, and the name stuck with the latter two.

What it led to

  • Cauchy's theory of complex-variable functions (1814)
  • Riemann's dissertation on function theory (1851) and the geometry of Riemann surfaces

Links

Sources✓ verified 2026-09-28