var y3 = w.multiply(THREE).multiply(x1).subtract(y1sqz1.shiftLeft(1)).shiftLeft(2).multiply(y1sqz1).subtract(w.square().multiply(w)).mod(this.curve.q);
                var z3 = y1z1.square().multiply(y1z1).shiftLeft(3).mod(this.curve.q);

                return new ECPoint(this.curve, this.curve.fromBigInteger(x3), this.curve.fromBigInteger(y3), z3);
            },
            negate: function() {
                return new ECPoint(this.curve, this.x, this.y.negate(), this.z);
            },
            isI