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Antoni Zygmund. Doctoral students. Peter Sarnak. Paul Joseph Cohen (April 2, 1934 – March 23, 2007) [1] was an American mathematician. He is best known for his proofs that the continuum hypothesis and the axiom of choice are independent from Zermelo–Fraenkel set theory, for which he was awarded a Fields Medal. [2]
A choice function (also called selector or selection) is a function f, defined on a collection X of nonempty sets, such that for every set A in X, f (A) is an element of A. With this concept, the axiom can be stated: Axiom— For any set X of nonempty sets, there exists a choice function f that is defined on X and maps each set of X to an ...
Set theory as conceived by Georg Cantor assumes the existence of infinite sets. As this assumption cannot be proved from first principles it has been introduced into axiomatic set theory by the axiom of infinity, which asserts the existence of the set N of natural numbers. Every infinite set which can be enumerated by natural numbers is the ...
The continuum hypothesis states that the set of real numbers has minimal possible cardinality which is greater than the cardinality of the set of integers. That is, every set, S, of real numbers can either be mapped one-to-one into the integers or the real numbers can be mapped one-to-one into S.
In set theory, a branch of mathematics, the minimal model is the minimal standard model of ZFC . The minimal model was introduced by Shepherdson ( 1951, 1952, 1953) and rediscovered by Cohen (1963) . The existence of a minimal model cannot be proved in ZFC, even assuming that ZFC is consistent, but follows from the existence of a standard model ...
Set theory is the branch of mathematical logic that studies sets, which can be informally described as collections of objects.Although objects of any kind can be collected into a set, set theory — as a branch of mathematics — is mostly concerned with those that are relevant to mathematics as a whole.
The inclusive or operation in a Boolean algebra. (In ring theory it is used for the exclusive or operation) ~. 1. The difference of two sets: x ~ y is the set of elements of x not in y. 2. An equivalence relation. \. The difference of two sets: x \ y is the set of elements of x not in y.
In many popular versions of axiomatic set theory, the axiom schema of specification, [ 1 ] also known as the axiom schema of separation (Aussonderungsaxiom), [ 2 ]subset axiom 3, axiom of class construction, [ 4 ] or axiom schema of restricted comprehension is an axiom schema. Essentially, it says that any definable subclass of a set is a set.