Extendible cardinal

From Wikipedia, the free encyclopedia

In mathematics, a cardinal number κ is η-extendible if and only if for some λ there is a nontrivial elementary embedding j of

Vκ+η

into

Vλ

where κ is the critical point of j.

κ is an extendible cardinal if and only if it is η-extendible for every ordinal number η.

Vopenka's principle implies the existence of extendible cardinals. All extendible cardinals are supercompact cardinals.

[edit] See also

[edit] References

"A cardinal κ is extendible if and only if for all α>κ there exists β and an elementary embedding from V(α) into V(β) with critical point κ." -- "Restrictions and Extensions" by Harvey M. Friedman http://www.math.ohio-state.edu/~friedman/pdf/ResExt021703.pdf

  • Kanamori, Akihiro (2003). The Higher Infinite : Large Cardinals in Set Theory from Their Beginnings, 2nd ed, Springer. ISBN 3-540-00384-3.