Integrals around general boundaries
P. J. Daniell · Bulletin of the American Mathematical Society · 1918
INTEGRALS AROUND GENERAL BOUNDARIES.65 25 m .The system of neighborhoods SS m for fixed m covers O and may be replaced by a finite subsystem, 8S ml , 23 m2 , . . .SS wfc ; such that each point of O is interior to some class 33 mfc and each class S5 mfc is a neighborhood of a point Q mk of the class O. Let © be the class of all points Q mk .Since every point P of O is interior to some set SB mfc , it follows from condition (4) that Q mk is contained in the neighborhood 8S m of P. Therefore P is a limiting point of the class ( §.