Contextual Refinement of Higher-Order Concurrent Probabilistic Programs - Formalization Artifact This repository contains the development of the Foxtrot logic, in the PLDI 2026 submission "Contextual Refinement of Higher-Order Concurrent Probabilistic Programs". Contents The file foxtrot-base-image.zip contains a virtual machine image containing the Foxtrot repository with all the dependencies installed. The file foxtrot-repo.zip contains the same Foxtrot repository. Usage Please refer to the README.md in the foxtrot-base-image and foxtrot-repo folders. In summary, after initiating the VM image from foxtrot-base-image, cd directly into foxtrot, call eval $(opam env) and directly call dune build (or dune build --display=short) since all dependencies are installed. Otherwise, follow the instructions to install opam, rocq, and other dependencies on your own machine to compile the files in foxtrot-repo. Comment A paper mapping table is also provided in paper_mapping.md in foxtrot-repo, and in the foxtrot directory after initiating the VM image. Warnings of the following form can be safely ignored.Warning: in file xxx, library xxx is required from root Coquelicot and has not been found in the loadpath! [module-not-found,filesystem,default] Acknowledgements This work was supported in part by the National Science Foundation, grant no. 2338317, a Villum Investigator grant, no. 25804, Center for Basic Research in Program Verification (CPV), from the VILLUM Foundation, and the European Union (ERC, CHORDS, 101096090). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them.