Invited Talk.- Ackermannian Completion of Separators.- Infinite Games.- Fair Omega-regular Games.- Stochastic Window Mean-Payoff Games.- Symbolic Solution of Emerson-Lei Games for Reactive Synthesis.- Parity Games on Temporal Graphs.- Categorical Semantics.- Drawing from an Urn is Isometric.- Enriching Diagrams with Algebraic Operations.- Monoidal Extended Stone Duality.- Towards a Compositional Framework for Convex Analysis (with Applications to Probability Theory).- Automata and Synthesis.- Determinization of Integral Discounted-Sum Automata is Decidable.- Checking History-Determinism is NP-hard for Parity Automata.- Tighter Construction of Tight Büchi Automata.- Synthesis with Privacy Against an Observer.

The two open access volumes LNCS 14574 and 14575 constitute the proceedings of the 27th International Conference on Foundations of Software Science and Computation Structures, FOSSACS 2024, which took place in Luxembourg in April 2024.The 24 full papers included in this book were carefully reviewed and selected from 79 submissions. They were organized in topical sections as follows: Part I: Infinite games; categorical semantics; automata and synthesis; Part II: Types and programming languages; logic and proofs; infinite-state systems.

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