Function check_reduction_claim 

pub fn check_reduction_claim(
    cells: &[RCell],
    out: RSrc,
    init: f64,
    frames: usize,
    claim: &RangeClaim,
) -> bool

Replay a STREAMED-REDUCTION claim: the same cells run once per frame with input 0 the element box and input 1 the carried accumulator (starting at init); the claim’s per-node bounds must contain the HULL of every frame’s replayed bounds, the claim’s input-1 box must contain the whole accumulator trajectory, and every claimed bound must respect the rails and the noise floor. Fail-closed on any malformation, divergence, or a frame count of zero.