This FLOPS 2026 constitutes the proceedings of the 18th International Symposium on Functional and Logic Programming, FLOPS 2026, held in Tsukuba, Japan, in May 26-28, 2026.

The 14 full papers and 2 invited talks presented in this volume were carefully reviewed and selected from 25 submissions. They were organized in topical sections as follows:.Lambda Calculus and Type Theory; Term Rewriting; Programming Language Semantics; Programming Language Compilers; Functional; Logic and Functional-Logic Programming; SAT solving; and applications thereof.

Inhalt

.- Finite Functional Programming: or, LAMBDA: the Ultimate Predicate.

.- Demonic Dynamic Logic Programming.

.- Breccia: A Functional DSL Compiled to Egglog for Test Input Generation.

.- Finding Programming Faults Even When Large Parts of the Code have Disappeared.

.- Unifying Hindsight and Foresight: Lazy Cost Analysis as Functional Logic Programming.

.- Visualizing miniKanren Search with a Fine-Grained Small-Step Semantics.

.- More Fun with Monoids.

.- Optimizing Mesh Booleans by Being Lazy (System Description).

.- Computing Supported Models via Transformation to Stable Models.

.- Probabilistic Linear Logic Programming with an application to Bayesian Networks computations.

.- Matrix Coeffect Algebra for Interdependent Context Requirements.

.- Test Your Polymorphic Functions with Boolean Values.

.- Automatic Knowledge Gap Detection and Plan Validation Using Counterfactual Justifications.

.- Dynamic Programming and Tabled Logic Programming for Encoding Single-Constant Multiplication into SAT (Declarative Pearls).