%T A Process Algebraic View of Input/Output Automata %R 10.1016/0304-3975(95)92307-J %P 391-423 %J Theoretical Computer Science %A Rocco De Nicola %A Roberto Segala %D 1995 %I Elsevier %L eprints366 %X Input/output automata are a widely used formalism for the specification and verification of concurrent algorithms. Unfortunately, they lack an algebraic characterization, a formalization which has been fundamental for the success of theories like CSP, CCS and ACP. We present a many-sorted algebra for I/O automata that takes into account notions such as interface, input enabling, and local control. It is sufficiently expressive for representing all finitely branching transition systems; hence, all I/O automata with a finitely branching transition relation. Our presentation includes a complete axiomatization of the external trace preorder relation over recursion-free processes with input and output. %V 138 %N 2