96 search results - page 1 / 20 » Long Borel hierarchies |
MLQ
2008
13 years 9 months ago
2008
We show that there is a model of ZF in which the Borel hierarchy on the reals has length 2. This implies that 1 has countable cofinality, so the axiom of choice fails very badly i...
ICALP
2004
Springer
14 years 3 months ago
2004
Springer
We first consider infinite two-player games on pushdown graphs. In previous work, Cachat, Duparc and Thomas [4] have presented a winning decidable condition that is Σ3-complete ...
APAL
2010
13 years 10 months ago
2010
We analyze the degree-structure induced by large reducibilities under the Axiom of Determinacy. This generalizes the analysis of Borel reducibilities given in [1], [6] and [5] e.g...
JSYML
2006
13 years 9 months ago
2006
We investigate diagonal actions of Polish groups and the related intersection operator on closed subgroups of the acting group. The Borelness of the diagonal orbit equivalence rela...
CORR
2010
Springer
13 years 10 months ago
2010
Springer
This paper is a continuation of the study of topological properties of omega context free languages (-CFL). We proved in [Topological Properties of Omega Context Free Languages, T...