This LNCS volume constitutes the proceedings of the International Joint Conference on Rough Sets, IJCRS 2026, held in Cádiz, Spain, during May 2026.The 27 full papers included in this book were carefully reviewed and selected from 106 submissions. These papers focus on following topical sections: Foundations and Models of Rough Sets; Computational Intelligence and Three-Way Decision.
.- Foundations and Models of Rough Sets.- New Equivalence Relations in Rough Set Theory..- A Formal Framework for Ontology-Driven Data Pre-processing Based on Information Systems over Ontological Graphs..- Game-Theoretic Decision Rough Sets for Active Planning of Autonomous Vehicles in Dynamic Interactions..- Hybrid Neighborhood Rough Set via Consistency Sample Selection for Multi-granularity Interpretable Modeling..- Non-averaging generalization of Choquet-like Copula-based integral with application to fuzzy-rough rule-based classification systems..- Application of a supervised fuzzy object selection algorithm for outlier identification..- Scalable OWA-based FRNN for Multi-Class Imbalanced Classification..- Computational Intelligence.- Diversity Clustering: A Soft Clustering Model Inspired by Ecological Diversity..- Concept-Dependent Granulation with Bootstrap and Smote Methods..- A Pessimistic Multi-Granulation Rough Bipolar Pythagorean Framework for Medical Decision-Making..- A Multi-Granularity Collaborative Genetic Algorithm for Truck-Drone Routing Problem..- Granular-Ball Embedding Clustering with Local Structure Preservation..- Multi-granularity Anomaly Detection via Attribute Subset Sequences Based on Fuzzy Entropy..- Deriving Dependency and Conflict Graphs from Configurable Software via Association Rules..- Concept multilattices for non-commutative conjunctors with truth-stressing hedges..- Triadic Context Simplification Based on Combination Reduction in TCA..- Strong and Weak Approximation Operators in Multi-Source Neighbourhood Systems..- Three-Dimensional Path Planning Using Mereological Potential Field..- A Survey on Multimodal Human-Machine Interaction in Smart Cockpits..- Out-of-Distribution Detection using Mesoscopic Boundary-Constrained Generative Adversarial Networks..- A Controllable Multi-space Feature Disentanglement Framework for Open-Domain Dialogue Generation..- Three-Way Decision.- Conceptual Models for Imbalanced Classification Based on Three-Way Bayesian Confirmation..- Semantics of the Boundary Region in Three-way Classification..- Three-way conflict analysis: Feasible strategies based on fuzzy rough sets and regret theory..- Three-way conflict analysis within multi-scale situation tables..- An Ensemble Method for Constructing Three-Way Decision Rules with Granular Rough Sets..- A probabilistic intersection measure for interval sets and its three-way decision model for image retrieval.