LinkedIn's ESP partitions embeddings into per-objective subspaces, tunable at serving time

_reachsumit · x · 2026-09-28

LinkedIn researchers propose Embedding Subspace Partitioning (ESP) for multi-objective retrieval. Standard bi-encoders collapse relevance, engagement, and revenue signals into one static embedding, so trade-offs can't shift without retraining.

ESP decomposes the embedding into task-aware subspaces scored via a weighted sum, with weights tunable at serving time. It uses the model's end-of-sequence token as a delimiter with segment-aware attention masking and position-encoding resets to keep subspaces isolated in one forward pass, and serves via GPU-accelerated exhaustive kNN over a single concatenated index—no per-objective ANN infrastructure needed.

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