Noun
the branch of pure mathematics that deals with the nature and relations of sets
Source: WordNetSet theory in sheep's clothing. Willard van Orman Quine
Minimalism now is a reaction to what came before. It's absolutely of its time. Music moved into the set theory thing, and moved out of it. Harrison Birtwistle
The emphasis on mathematical methods seems to be shifted more towards combinatorics and set theory - and away from the algorithm of differential equations which dominates mathematical physics. John von Neumann
Henri Poincaré thought the theory of infinite sets a grave malady and pathologic. "Later generations," he said in 1908, "will regard set theory as a disease from which one has recovered. Morris Kline
A formulation of set theory that does not include the axiom of replacement will likely include some form of the axiom of separation, to ensure that its models contain a sufficiently rich collection of sets. Source: Internet
Already, in 1908, Arthur Moritz Schoenflies found in the second part of his report on set theory, that the newer theory of ordered sets (i. Source: Internet