CS676: Knowledge Representation Fall, 1999

Homework 3
Due at start of class, October 7, 1999

Stuart C. Shapiro
Department of Computer Science and Engineering
State University of New York at Buffalo

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1. Using a Fitch-style inference method for Relevance Logic, prove
   ((P -> Q) & (Q -> R)) -> (P -> R)

2. Prove that (L(A) & L(A => B)) => L(B) is valid in modal logics.

3. Prove that (L(A) & (A => B)) => L(B) is not valid in modal logics.

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Stuart C. Shapiro <shapiro@cse.buffalo.edu>