Schroeder-Bernstein theorem

Schroeder-Bernstein theorem

[′shrād·ər ′bərn‚stīn ‚thir·əm]
(mathematics)
If a set A has at least as many elements as another set B and B has at least as many elements as A, then A and B have the same number of elements.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.