Tabular and Pretabular Varieties of MTL-algebras -- Cyclic Group Spectra for Some Small Relation Algebras.-Presenting Interval Pomsets with Interfaces -- Irrationality of Process Replication for Higher-Dimensional Automata -- Monotone Ω-Sup-Fuzzy Relations: Converse and Complementation -- On the Structure of Balanced Residuated Partially-ordered Monoids -- Complete Congruences of Completely Distributive Lattices -- A Matrix-oriented View of Bisimulations Quotients over Dioid-labeled Transition Systems -- Restructuring a Concurrent Refinement Algebra -- Frames and Spaces for Distributive Quasi Relation Algebras and Involutive FL-algebras -- Data Migration under a Changing Schema in Ampersand -- Using Matrix Sparsification to Solve Tropical Linear Vector Equations -- Undecidability of the Positive Calculus of Relations with Transitive Closure and Difference: Hypothesis Elimination Using Graph Loops -- L-Fuzzy Weak Preference, Preference, and Choice Relations -- Lifting Star-autonomy.

This book constitutes the refereed proceedings of the 21st International Conference, RAMiCS 2024, held in Prague, Czech Republic, during August 19–22, 2024. The 15 full papers presented in this book were carefully reviewed and selected from 21 submissions. They focus on mathematical foundations to applications as conceptual and methodological tools in computer science and beyond.