arxivcs.LGcs.CL2026-07-04
Uncertainty-gated selection for block-sparse attention
Block-sparse attention scales long-context language models by replacing the O(N^2) softmax with a per-query top-k selection over key blocks. This cutoff is myopic: when the k-th and (k+1)-th blocks are nearly tied in score, the selector commits without spending extra budget, and…