Épistémologie du transfini
Extendibility of embeddings
Forcing in the alternative set theory. I
The technique of forcing is developed for the alternative set theory (AST) and similar weak theories, where it can be used to prove some new independence results. There are also introduced some new extensions of AST.
Forcing in the alternative set theory. II
By the technique of forcing, some new independence results are proved for the alternative set theory (AST) and similar weak theories: The scheme of choice is independent both of AST and of second order arithmetic, axiom of constructibility is independent of AST plus schemes of choice.
Generic extensions of models of ZFC
The paper contains a self-contained alternative proof of my Theorem in Characterization of generic extensions of models of set theory, Fund. Math. 83 (1973), 35–46, saying that for models of ZFC with same ordinals, the condition implies that is a -C.C. generic extension of .
HOD-supercompactness, Indestructibility, and Level by Level Equivalence
In an attempt to extend the property of being supercompact but not HOD-supercompact to a proper class of indestructibly supercompact cardinals, a theorem is discovered about a proper class of indestructibly supercompact cardinals which reveals a surprising incompatibility. However, it is still possible to force to get a model in which the property of being supercompact but not HOD-supercompact holds for the least supercompact cardinal κ₀, κ₀ is indestructibly supercompact, the strongly compact and...
I teoremi di assolutezza in teoria degli insiemi: prima parte
Questa è la prima parte di una articolo espositivo dedicato ai teoremi di assolutezza, un argomento che sta assumendo un’importanza via via più grande in teoria degli insiemi. In questa prima parte vedremo come le questioni di teoria dei numeri non siano influenzate da assunzioni insiemistiche quali l’assioma di scelta o l’ipotesi del continuo.
I teoremi di assolutezza in teoria degli insiemi: seconda parte
Questa è la seconda parte dell’articolo espositivo [A]. Qui vedremo come siapossibile utilizzare il forcinge gli assiomi forti dell’infinito per dimostrare nuovi teoremi sui numeri reali.
Internal and forcing models for the impredicative theory of classes [Book]
Linear orders and MA + ¬wKH
I prove that the statement that “every linear order of size can be embedded in ” is consistent with MA + ¬ wKH.
Nonnormality points of βX∖X
Let X be a crowded metric space of weight κ that is either -like or locally compact. Let y ∈ βX∖X and assume GCH. Then a space of nonuniform ultrafilters embeds as a closed subspace of (βX∖X)∖y with y as the unique limit point. If, in addition, y is a regular z-ultrafilter, then the space of nonuniform ultrafilters is not normal, and hence (βX∖X)∖y is not normal.
O prvním Hilbertově problému (Hypotéza kontinua a axióm výběru)
O riešení niektorých nerozhodnutelných topologických problémov
On almost-free modules over complete discrete valuation rings
On Cartesian Powers of a Rational Group.
On collections of almost disjoint families
On full Suslin trees
Progrès récents sur l’hypothèse du continu
Les travaux récents de Woodin ont considérablement renouvelé la théorie des ensembles en lui apportant une intelligibilité globale et en restaurant son unité. Pour la première fois, ses résultats ouvrent une perspective réaliste de résoudre le problème du continu, et, à tout le moins, ils établissent le caractère irréfutablement signifiant et précis de celui-ci.
Propositional extensions of [Book]
Provident sets and rudimentary set forcing
Using the theory of rudimentary recursion and provident sets expounded in [MB], we give a treatment of set forcing appropriate for working over models of a theory PROVI which may plausibly claim to be the weakest set theory supporting a smooth theory of set forcing, and of which the minimal model is Jensen’s . Much of the development is rudimentary or at worst given by rudimentary recursions with parameter the notion of forcing under consideration. Our development eschews the power set axiom. We...