ЛЕММА
Lemma
From Greek "proposition". In mathematics, a theorem proved for the sake of its use in proving another theorem; in logic, a conditional conclusion (premiss of a syllogism). Depending on the number of consequences involved in the larger premiss (according to the members of disjunctive propositions in the smaller), Lemma becomes a dilemma, trilemma or multilemma. The most common form of Lemma is the dilemma, implying the need to choose between two alternatives.
Лемма
(Греч. lemma) в математике, вспомогательное предложение, употребляемое при доказательстве одной или нескольких теорем. Термин «Л.» введён древнегреческими геометрами; особенно часто встречается у Архимеда.