Correct cardinal: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
CreeperBomb (talk | contribs) (Undo revision 684 by Cobsonwabag (talk)) Tag: Undo |
||
(One intermediate revision by one other user not shown) | |||
(No difference)
|
Latest revision as of 16:50, 25 March 2024
A \(\Sigma_n\)-correct cardinal is a cardinal \(\kappa\) such that \(V_\kappa\) is a \(\Sigma_n\)-elementary substructure of \(V\), where \(\Sigma_n\) is from the Lévy hierarchy.[Citation needed]
A regular cardinal \(\kappa\) is \(\Sigma_2\)-correct iff for every first-order formula \(\phi(x)\) and any \(x\in H_\kappa\), if \(\exists\alpha(H_\alpha\vDash\phi(x))\), then there is a \(\beta<\kappa\) such that \(H_\beta\vDash\phi(x)\). [1]