Reference · Signed rationals
rainbow.math.rational.signed.distance-multiply-nonnegative
Nonnegative signed multiplication bounds quotient-safe distance. Rather than requiring an absolute-value product theorem, the proof opens a distance bound into its two deviation rows. Nonnegative multiplication preserves each row, distributivity identifies the scaled subtraction, and negation congruence identifies the reverse deviation. Folding the rows back yields `d(w*x,w*y) <= w*d(x,y)` for `0 <= w`, exactly the component law needed by nonnegative matrix rows. Native, kernel-checked, and axiom-free on D63.
signed/distance-multiply-left-nonnegative
signed/distance-multiply-left-nonnegative : (weight left right : ℚ) (weight-nonnegative : 0 ≤ weight) → signed/distance (weight · left) (weight · right) ≤ weight · signed/distance left right
0 = signed/zero· = signed/multiplyℚ = signed/SignedRational≤ = signed/at-most