Hartogs number

短语

词形变化

Hartogs numbers 复数 Hartogs numbers

别名

Hartogs' number

释义与例句

n.
  1. 1.

    For a given set X, the cardinality of the least ordinal number α such that there is no injection from α into X.

    数学

    1973 [North-Holland], Thomas J. Jech, The Axiom of Choice, 2013, Dover, page 160, Let p be an infinite cardinal, |X|=p and let א=א(p) be the Hartogs number of p.

    1995, The Bulletin of Symbolic Logic, Volume 1, Association for Symbolic Logic, page 139, If the Power Set Axiom is replaced by "א(x) is bound for every x" where א(x)={a|∃f(f is one-to-one function from a into x)}, then the theory is denoted by ZFH (H stands for Hartogs' Number).

词源

After German-Jewish mathematician Friedrich Hartogs (1874–1943).

来源：wiktionary