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Set constraints are inclusions between expressions denoting sets of trees. The eeciency of their satissabil-ity test is a central issue in set-based program analysis , their main application domain. We introduce the class of set constraints with intersection (the only operators forming the expressions are constructors and intersection) and show that its(More)
We study the control reachability problem in the Dolev-Yao model of cryptographic protocols when principals are represented by tail recursive processes with generated names. We propose a conservative approximation of the problem by reduction to a non-standard collapsed operational semantics and we introduce checkable syntactic conditions entailing the(More)
We consider the two-variable logic with counting quantifiers (C<sup>2</sup>) interpreted over finite structures that contain two forests of ranked trees. This logic is strictly more expressive than standard C<sup>2</sup> and it is no longer a fragment of first-order logic. In particular, it can express that a structure is a ranked tree, a cycle, or a(More)