Back Halbnorm German Seminorma Spanish Poolnorm Estonian Semi-norme French נורמה-למחצה HE Seminorma Italian 半ノルム Japanese Seminorma Portuguese Полунорма Russian Напівнорма Ukrainian
In mathematics, particularly in functional analysis, a seminorm is a norm that need not be positive definite. Seminorms are intimately connected with convex sets: every seminorm is the Minkowski functional of some absorbing disk and, conversely, the Minkowski functional of any such set is a seminorm.
A topological vector space is locally convex if and only if its topology is induced by a family of seminorms.