Automata and Fixed Point Logic: a Coalgebraic Perspective Yde Venema Abstract: This paper generalizes existing connections between automata and logic to a coalgebraic level. Let F be a standard endofunctor on Set that preserves weak pullbacks. We introduce various notions of F-automata, devices that operate on pointed F-coalgebras. The criterion under which such an automaton accepts or rejects a pointed coalgebra is formulated in terms of an infinite two-player graph game. We also introduce a language of coalgebraic fixed point logic for F-coalgebras, and we provide a game semantics for this language. Finally we show that any formula P of the language can be transformed into an F-automaton A(P) which is equivalent to P in the sense that A(P) accepts precisely those pointed F-coalgebras in which P holds.