# Online Encyclopedia

# Lemma

In mathematics, a **lemma** expresses a minor theorem, of interest primarily because it serves in the proof of a major result. In a few cases, a lemma becomes well-known in its own right; this can occur when a lemma is a particularly useful restatement of another result. See Zorn's lemma and Farkas's lemma .

In linguistics, and particularly in morphology, a **lemma** comprises the canonical form of a word. Lemmas have especial significance in highly inflected languages such as Czech.

In Terry Pratchett's Discworld series, the **shadowing lemma** is an animal which exists in only 2 dimensions and eats mathematicians.

Last updated: 02-16-2005 08:58:51

Last updated: 02-26-2005 04:50:46