📜 Theorem, law or theory

Bolzano–Weierstrass theorem

Teorema de Bolzano-Weierstrass

Date
1817 (Bolzano) / c. 1865 (redescubierto por Weierstrass) · confidence medium
Place
Prague, Bohemia (present-day Czech Republic)
Credited to
Bernard Bolzano; independently rediscovered and popularized by Karl Weierstrass about fifty years later
Field
Knowledge & symbols

What was discovered

As an auxiliary step in his proof of the intermediate value theorem, Bolzano showed that every bounded sequence of real numbers contains a convergent subsequence. The result went unnoticed until Weierstrass independently proved it again and turned it into a central theorem of real analysis in its own right.

What it led to

  • Sequential compactness in real analysis
  • Rigorous foundations of topology

Built on

  • Bolzano's rigorous definition of limit and continuity

Links

Sources✓ verified 2026-09-28