For example, the rule of necessitation from A 's being a theorem to OA 's being a theorem is rejected. Thus, it does not say that all theorems ought to be the case. This theory avoids the analogs of the paradoxes of implication that appear in standard logics of counterfactuals. Relevant logics have been used in computer science as well as in philosophy. Linear logics, a branch of logic discoverd by the French logician Girard, is a logic of computational resources.
Linear logic is, in fact, a weak relevant logic with the addition of two operators.
What follows is a brief list of some of the more influential works in the field and works that are referred to above. Excellent work and still the standard books on the subject. They tend to be Routley's views rather than the views of the other authors and are fairly radical even for relevant logicians. Volume II is currently in the works. CSLI pp 3-27.