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TARK
2007
Springer

What can we achieve by arbitrary announcements?: A dynamic take on Fitch's knowability

14 years 20 days ago
What can we achieve by arbitrary announcements?: A dynamic take on Fitch's knowability
Public announcement logic is an extension of multi-agent epistemic logic with dynamic operators to model the informational consequences of announcements to the entire group of agents. We propose an extension of public announcement logic with a dynamic modal operator that expresses what is true after any announcement: ϕ expresses that ϕ is true after an arbitrary announcement ψ. As this includes the trivial announcement , one might as well say that ϕ expresses what remains true after any announcement: it therefore corresponds to truth persistence after (definable) relativisation. The dual operation ♦ϕ expresses that there is an announcement after which ϕ. This gives a perspective on Fitch’s knowability issues: for which formulas ϕ does it hold that ϕ → ♦Kϕ? We give various semantic results, and we show completeness for a Hilbert-style axiomatisation of this logic.
Philippe Balbiani, Alexandru Baltag, Hans P. van D
Added 09 Jun 2010
Updated 09 Jun 2010
Type Conference
Year 2007
Where TARK
Authors Philippe Balbiani, Alexandru Baltag, Hans P. van Ditmarsch, Andreas Herzig, T. Hoshi, Tiago De Lima
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