def dge_z

bend-collections-laws-math@1.0.0.0 · proofs/math/typed/f64tools.bend:181

import Base
import bend-collections-laws-math@1.0.0.0/src/math/f64.bend as F
import bend-collections-laws-math@1.0.0.0/proofs/lib/logic.bend as L
import bend-collections-laws-math@1.0.0.0/proofs/lib/lemmas/proofs/nat_algebra.bend as NA

181# the scale of a finite double is at least 1926 (the subnormal scale)
182def dge_z(+e: Nat, +z: Bool) -> {Nat.is_le(63n, F.dexp_z(e, z)) == True{} : Bool}:
183  match z:
184    case True{}:
185      {==}
186    case False{}:
187      L.subst(Nat, t => {Nat.is_le(63n, t) == True{} : Bool}, Nat.add(1925n, e), Nat.add(e, 1925n), NA.add_comm(1925n, e), {==})