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Umbral

From Wikipedia, the free encyclopedia

Umbral is derived from the Latin word umbra, meaning "shadow". It is also the Spanish and Portuguese word for "threshold" and is sometimes used as a surname in those languages.

Umbral may also refer to:

  • Umbral calculus, the surprising similarity between seemingly unrelated polynomial equations and certain shadowy techniques used to "prove" them
  • Umbral moonshine, a mysterious connection between Niemeier lattices and Ramanujan's mock theta functions
  • Francisco Umbral (1932–2007), Spanish journalist, novelist, biographer and essayist

See also

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