Worked on the pymc-devs/pytensor repository to deliver canonicalization rewrites for the JoinDims and SplitDims operations, simplifying them to identity, expand_dims, or squeeze forms. This approach improved graph optimization and tensor manipulation by enabling more straightforward graph reasoning and backend dispatch. The work was implemented in Python and included comprehensive unit testing to ensure the correctness of the transformations. Partial fixes for issue #1843 were incorporated, laying the groundwork for future performance improvements. The focus during this period was on enhancing correctness, increasing test coverage, and establishing a more maintainable codebase for subsequent optimization efforts.