Function rtExpr

src/compute-engine/rubi/rubi-utils.ts:1266–1274

Rt[u, n] = RtAux[TogetherSimplify[u], n] — Rubi's canonical n-th root. * RtAux DISTRIBUTES the root over products/quotients and pairs sign flips * with negative-form sum factors. This composition is branch-unsound in * general; it is exactly Mathematica's principal-branch rendering, which * Rubi

(u: Expression, n: number | Expression)

      t.operator === 'Multiply' &&
      !!t.ops &&
      t.ops.filter((o) => o.symbol === x).length === 1 &&
      t.ops.every((o) => o.symbol === x || !o.has(x))
    );
  };
  if (!u.has(x)) return false;
  if (isBX(u)) return true;
  return (
    u.operator === 'Add' &&
    !!u.ops &&
    u.ops.filter((t) => !t.has(x)).length === u.ops.length - 1 &&
    u.ops.some((t) => isBX(t))
  );