Math.
a collection of sets in a topological space in which each point of the space has a neighborhood that intersects a finite number of sets of the collection.
Math.
a collection of sets in a topological space in which each point of the space has a neighborhood that intersects a finite number of sets of the collection.
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012