Commutative Doubly-idempotent Semirings Determined by Chains and by Preorder Forests.- A Relation-Algebraic Treatment of the Dedekind Recursion Theorem.- Hardness of Network Satisfaction for Relation Algebras with Normal Representations.- The Theta-Join as a Join With Theta.- Bisimilarity of Diagrams.- Generating Posets Beyond N.- Automated Algebraic Reasoning for Collections and Local Variables with Lenses.- Weakening Relation Algebras and FL 2-algebras.- Verifying the Correctness of Disjoint-Set Forests with Kleene Relation Algebras.- A Hierarchy of Algebras for Boolean Subsets.- Differential Hoare Logics and Refinement Calculi for Hybrid System with Isabelle/HOL.- Higher-Order Categorical Substructural Logic: Expanding the Horizon of Tripos Theory.- Expressive Power and Succinctness of the Positive Calculus of Relations.- Stone Dualities from Opfibrations.- Preorders, Partial Semigroups, and Quantales.- Counting and Computing Join-Endomorphisms In Lattices.- A Unary Semigroup Trace Algebra.- The Involutive Quantaloid of Completely Distributive Lattices.- Computer-Supported Exploration of a Categorical Axiomatization of Modeloids.- Sharpness in the Fuzzy World.