📜 Theorem, law or theory

Invariance of domain

Invarianza del dominio

Date
1912 · confidence high
Place
Amsterdam, Netherlands
Credited to
Proved by L. E. J. Brouwer in 1912, as an application of his algebraic topology techniques (mapping degree).
Field
Knowledge & symbols

What was discovered

Topology theorem stating that if an open subset of Rⁿ is mapped injectively and continuously into Rⁿ, its image is also open; a far from trivial result despite its intuitive appearance.

What it led to

  • Establishment of algebraic topology as a rigorous tool
  • Foundation for proving Rᵐ and Rⁿ are not homeomorphic when m≠n
  • Applications in manifold theory

Links

Sources✓ verified 2026-09-28