boolean isInfinity() {
      return this.z.equals(BigInteger.ZERO);
    }
Jacobian representation of elliptic curve points.

<p>The point (X, Y) is represented by a triple (x, y, z), where X = x/z^2 and Y = y/z^3.
java_src/src/main/java/com/google/crypto/tink/internal/EllipticCurvesUtil.java