Reference · Signed rationals
rainbow.math.rational.signed.no-zero-divisors
No-zero-divisors sub-foundation for strict convexity: nonzero facts and (building up) a != 0 -> b != 0 -> a*b != 0. Brick 1 first: 1 !~ 0.
nnrat/one-not-equivalent-zero
nnrat/one-not-equivalent-zero : → proposition/negation (1 = 0)
0 = nnrat/zero1 = nnrat/one= = nnrat/equivalent: equality of rational values
signed/one-not-equivalent-zero
signed/one-not-equivalent-zero : → proposition/negation (1 = 0)
0 = signed/zero1 = signed/one= = signed/equivalent: equality of rational values
signed/zero-less-than-one
signed/zero-less-than-one : → 0 < 1
0 = signed/zero1 = signed/one< = signed/less-than