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14 August 2008, Topological semantics for polymodal provability logic and infinitary combinatorics, Lev Beklemishev (Moskou, Münster)
Lev Beklemishev will report on a work in progress (jointly with Thomas Icard) on the problem of finding a complete topological semantics of polymodal provability logic GLP (due to Giorgi Japaridze). They isolate the concept of a GLP-space that turns out to encompass some structures prominent in set theory and ininitary combinatorics. In particular, the most natural "ordinal GLP spaces" are tightly related to the so-called stationary reflection principles. The existence of a complete semantics for GLP, and the mere nontriviality of topologies involved, is then dependent on various (large cardinal) axioms outside ZFC.
For more information, please contact karin at science.uva.nl
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