  Input/Output (I/O) logic is a general framework for reasoning about
conditional norms and/or causal relations. We streamline Bochman's causal I/O
logics via proof-search-oriented sequent calculi. Our calculi establish a
natural syntactic link between the derivability in these logics and in the
original I/O logics. As a consequence of our results, we obtain new, simple
semantics for all these logics, complexity bounds, embeddings into normal modal
logics, and efficient deduction methods. Our work encompasses many scattered
results and provides uniform solutions to various unresolved problems.
