{ "id": "1908.09664", "version": "v1", "published": "2019-08-26T13:18:14.000Z", "updated": "2019-08-26T13:18:14.000Z", "title": "$C^{(n)}$-Cardinals", "authors": [ "Joan Bagaria" ], "journal": "Arch. Math. Logic, (2012) 51:213-240", "categories": [ "math.LO" ], "abstract": "For each natural number $n$, let $C^{(n)}$ be the closed and unbounded proper class of ordinals $\\alpha$ such that $V_\\alpha$ is a $\\Sigma_n$ elementary substructure of $V$. We say that $\\kappa$ is a \\emph{$C^{(n)}$-cardinal} if it is the critical point of an elementary embedding $j:V\\to M$, $M$ transitive, with $j(\\kappa)$ in $C^{(n)}$. By analyzing the notion of $C^{(n)}$-cardinal at various levels of the usual hierarchy of large cardinal principles we show that, starting at the level of superstrong cardinals and up to the level of rank-into-rank embeddings, $C^{(n)}$-cardinals form a much finer hierarchy. The naturalness of the notion of $C^{(n)}$-cardinal is exemplified by showing that the existence of $C^{(n)}$-extendible cardinals is equivalent to simple reflection principles for classes of structures, which generalize the notions of supercompact and extendible cardinals. Moreover, building on results of \\cite{BCMR}, we give new characterizations of Vope\\v{n}ka's Principle in terms of $C^{(n)}$-extendible cardinals.", "revisions": [ { "version": "v1", "updated": "2019-08-26T13:18:14.000Z" } ], "analyses": { "keywords": [ "extendible cardinals", "large cardinal principles", "simple reflection principles", "usual hierarchy", "unbounded proper class" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }