Arne developed the FilterSubspaces Tensor Subspace Filtering API for the vespa-engine/vespa repository, delivering a new tensor function that enables selective filtering of tensor subspaces based on user-defined conditions. Using Java and leveraging expertise in API design and tensor operations, Arne implemented support for both mapped and dense dimensions, allowing the function to evaluate filters and construct resulting tensors for granular data selection. This addition addressed the need for more precise analytics and model training workflows by enabling targeted extraction of relevant data. The work demonstrated a focused approach to extending tensor functionality within a complex, production-grade Java codebase.