The search session has expired. Please query the service again.
The search session has expired. Please query the service again.
It is shown that in many forcing models there is no universal graph at the successors of regular cardinals. The proof, which is similar to the well-known proof for Cohen forcing, is extended to show that it is consistent to have no universal graph at the successor of a singular cardinal, and in particular at . Previously, little was known about universality at the successors of singulars. Analogous results show it is consistent not just that there is no single graph which embeds the rest, but that...
A model is presented in which the equivalence relation xCy iff L[x]=L[y] of equiconstructibility of reals does not admit a reasonable form of the Glimm-Effros theorem. The model is a kind of iterated Sacks generic extension of the constructible model, but with an “ill“founded “length” of the iteration. In another model of this type, we get an example of a non-Glimm-Effros equivalence relation on reals. As a more elementary application of the technique of “ill“founded Sacks iterations, we obtain...
We explore the possibility of forcing nonreflecting stationary sets of . We also present a generalization of Kanamori’s weakly normal filters, which induces stationary reflection.
We discuss the problem of whether there exists a restriction of the noncofinal ideal on that is normal.
The following statement is proved to be independent from : Let be a Tychonoff space with and . Then a union of less than of nowhere dense subsets of is a union of not greater than of nowhere dense subsets.
Currently displaying 1 –
10 of
10