We present an overview of some sequent calculi organised not for
"theorem-proving" but for proof search, where the proofs themselves
(and the avoidance of known proofs on backtracking) are objects of
interest. The main calculus discussed is that of Herbelin [1994] for
intuitionistic logic, which extends methods used in hereditary
Harrop logic programming; we give a brief discussion of similar
calculi for other logics. We also point out to some related work on
permutations in intuitionistic Gentzen sequent calculi that
clarifies the relationship between such calculi and natural
deduction.Centro de Matemática da Universidade do Minho (CMAT).União Europeia (UE) - Programa ESPRIT - BRA 7232 Gentzen
