import com.perisic.ring.*;
import java.math.*;

public class PolynomialExample {
public static void main(String [] args) {
    PolynomialRing P = new PolynomialRing(Ring.Z,"a,b");
    RingElt a = P.map("a^2 - b^2");
    RingElt b = P.map("(a - b)^2");

    RingElt d = P.gcd(a,b);
    System.out.println("gcd("+a+","+b+") = "+d+" (in "+P+")");
    }
}