Integral Forms of Twisted Quantum Affine Algebras and Quantum Frobenius

For twisted quantum affine algebras, we compare Lusztig's restricted integral form with the integral form generated by group-like toral elements and divided powers of real Drinfeld current modes. The two forms coincide over Z[q,q⁻¹] outside type A₂ₙ⁽²⁾. In type A₂ₙ⁽²⁾, the smallest ordinary localization over which they coincide is Z[q,q⁻¹][Φ₄ᵣ(q)⁻¹ r≥1] when $n=1$, and Z[q,q⁻¹][Φ₈ᵣ(q)⁻¹ r≥1] when n≥2, where Φₖ(q) are cyclotomic polynomials. In particular, no localization obtained by inverting finitely many nonzero Laurent polynomials suffices in this family.