# Isomorphism between \$Z[X,Y ]/(2Y−1)\$ and \$Z[frac{1}/{2}][X]\$

Hi I been trying to proof that $$Z(X,Y )/(2Y−1)$$ is isomorphic to $$Z({1}/{2})(X)$$ where$$Z({1}/{2})$$= $$frac{a}{2^n} : a ∈ Z, n ∈ N, n ≥ 0$$