Theory contraction and base contraction unified
Sven Ove Hansson · Journal of Symbolic Logic · 1993
Abstract One way to construct a contraction operator for a theory (belief set) is to assign to it a base (belief base) and an operator of partial meet contraction for that base. Axiomatic characterizations are given of the theory contractions that are generated in this way by (various types of) partial meet base contractions.