TreeWY: Speculative Verification for Gated DeltaNet Hybrids

TL;DR - TreeWY is a speculative-verification method for Gated DeltaNet hybrid models that eliminates per-draft-node recurrent-state snapshots. It reduces memory pressure during serving, enabling higher throughput, lower time-to-first-token, or wider draft trees when memory is the bottleneck.

• Uses a tree-structured WY transform and a single triangular solve to compute outputs for all draft nodes.
• Stores a compact pseudo-value matrix and reconstructs only the accepted recurrent state at commit time.
• Benchmarks on Qwen3.5 35B and 397B show reduced recurrent-state memory and KV-cache pressure at unchanged acceptance length.
• Wider, higher-acceptance draft trees become memory-affordable, though they do not yet improve throughput; non-memory-bound cases incur a few percent overhead.