hálfgrúpa

== Icelandic == === Etymology === From hálf- (“half-”) +‎ grúpa (“group”). === Noun === hálfgrúpa f (genitive singular hálfgrúpu, nominative plural hálfgrúpur) (mathematics) a semigroup; (any set for which there is a binary operation that is both closed and associative) ==== Declension ==== ==== Derived terms ==== styttin hálfgrúpa (“cancellation semigroup”) hálfgrúpumótun (“semigroup homomorphism”) hálfgrúpa með hlutleysu (“semigroup with identity element, monoid”)