Function posQ

src/compute-engine/rubi/rubi-utils.ts:1122–1130

Rubi PosQ[u] := PosAux[TogetherSimplify[u]] — the Together step is * semantic, not cosmetic: PosAux[a − bc/d] has First = a (positive form) * while the together'd (a·d − b·c)/d has First = −b·c (negative form). * Emulated with the asNumDen/expand rational normalizer.

(e: Expression)

  // Mathematica's automatic Together would have flattened)
  const vals = args.map((a) => {
    const e = build(a, ctx);
    return realNum(e) ?? realNum(safeSimplify(e)) ?? ratConstant(e);
  });
  for (let i = 0; i + 1 < vals.length; i++) {
    const a = vals[i];
    const b = vals[i + 1];
    if (a === null || b === null || !cmp(a, b)) return false;
  }
  return true;
}

function intCmp(