Title: Arity hierarchy for temporal logic
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Speaker: Alex Rabinovich
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Abstract
The Kamp theorem states that the first-order monadic logic of order
has the same expressive power over linerar orders
 as the temporal logic with two binary
modalitis: ``Until" and ``Since"
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The first part 
of this talk   surveys Temporal Logics and  classical  expressive
completeness results.
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In the second part I will prove that, in contrast to the Kamp theorem,
for every n there is a monadic
formula of arity n which is not equivalent over the trees
to any temporal logic formula wich uses only  modalities of arity < n