Automating Software Re-Engineering (Introduction to the ISoLA 2020 Track) -- Formal Verification of Developer Tests: a Research Agenda Inspired by Mutation Testing -- Modular Regression Verification for Reactive Systems -- Finding Idioms in Source Code using Subtree Counting Techniques -- Parametric Timed Bisimulation -- A Unifying Framework for Dynamic Monitoring and a Taxonomy of Optimizations -- Thirty-seven years of relational Hoare logic: remarks on its principles and history -- Safer Parallelization -- Refactoring and Active Object Languages -- Rigorous Engineering of Collective Adaptive Systems -- Introduction to the 3rd Track Edition -- Composition of Component Models - a Key to Construct Big Systems -- Degrees of Autonomy in Coordinating Collectives of Self-Driving Vehicles -- Engineering semantic self-composition of services through tuple-based coordination -- A Dynamic Logic for Systems with Predicate-based Communication -- Behavioural Abstractions for Collective AdaptiveSystems -- Verifying AbC specifications via emulation -- Adaptive Security Policies -- Capturing Dynamicity and Uncertainty in Security and Trust via Situational Patterns -- Guaranteeing Type Consistency in Collective Adaptive Systems -- Epistemic Logic in Ensemble Specification -- FScaFi: a Core Calculus for Collective Adaptive Systems Programming -- Writing Robotics Applications with X-Klaim -- Measuring Adaptability and Reliability of Large Scaled Systems -- Centrality-preserving exact reductions of Multi-Layer Networks -- Towards Dynamic Dependable Systems through Evidence-Based Continuous Certification -- Forming Ensembles at Runtime: A Machine Learning Approach -- Synthesizing Control for a System with Black Box Environment, based on Deep Learning -- A Formal Model For Reasoning About The Ideal Fitness In Evolutionary Processes -- A case study of policy synthesis for swarm robotics. -- Maple-Swarm: Programming Collective Behavior for Ensembles by extending HTN-Planning -- Swarm and Collective Capabilities for Multipotent Robot Ensembles.

The three-volume set LNCS 12476 - 12478 constitutes the refereed proceedings of the 9th International Symposium on Leveraging Applications of Formal Methods, ISoLA 2020, which was planned to take place during October 20-30, 2020, on Rhodes, Greece. The event itself was postponed to 2021 due to the COVID-19 pandemic. The papers presented were carefully reviewed and selected for inclusion in the proceedings. Each volume focusses on an individual topic with topical section headings within the volume: Part I, Verification Principles: Modularity and (De-)Composition in Verification; X-by-Construction: Correctness meets Probability; 30 Years of Statistical Model Checking; Verification and Validation of Concurrent and Distributed Systems. Part II, Engineering Principles: Automating Software Re-Engineering; Rigorous Engineering of Collective Adaptive Systems. Part III, Applications: Reliable Smart Contracts:State-of-the-art, Applications, Challenges and Future Directions; Automated Verification of Embedded Control Software; Formal methods for DIStributed COmputing in future RAILway systems. .