* must not both be identical to the values given in the first mapping. If only the {@code x}
     * values are identical, the transformation is vertical. If only the {@code y} values are
     * identical, the transformation is horizontal (i.e. the slope is zero).
     */
    public LinearTransformation and(double x2, double y2) {
      checkArgument(isFinite(x2) && isFinite(y2));

	}

	duration := ts2.Sub(ts1)
	y1, m1, d1 := ts1.Date()
	y2, m2, d2 := ts2.Date()

	switch timePart {
	case timePartYear:
		dy := int64(y2 - y1)
		if m2 > m1 || (m2 == m1 && d2 >= d1) {
			return FromInt(dy), nil
		}
		return FromInt(dy - 1), nil
	case timePartMonth:
		m1 += time.Month(12 * y1)
		m2 += time.Month(12 * y2)

		return FromInt(int64(m2 - m1)), nil
	case timePartDay:

{{.p}}B() *{{.Element}} { _{{.p}}BOnce.Do(func() { _{{.p}}B, _ = new({{.Element}}).SetBytes({{.B}}) }) return _{{.p}}B } // {{.p}}Polynomial sets y2 to x³ - 3x + b, and returns y2. func {{.p}}Polynomial(y2, x *{{.Element}}) *{{.Element}} { y2.Square(x) y2.Mul(y2, x) threeX := new({{.Element}}).Add(x, x) threeX.Add(threeX, x) y2.Sub(y2, threeX) return y2.Add(y2, {{.p}}B()) } func {{.p}}CheckOnCurve(x, y *{{.Element}}) error { // y² = x³ - 3x + b rhs := {{.p}}Polynomial(new({{.Element}}), x) lhs := ne...

{{.p}}B() *{{.Element}} { _{{.p}}BOnce.Do(func() { _{{.p}}B, _ = new({{.Element}}).SetBytes({{.B}}) }) return _{{.p}}B } // {{.p}}Polynomial sets y2 to x³ - 3x + b, and returns y2. func {{.p}}Polynomial(y2, x *{{.Element}}) *{{.Element}} { y2.Square(x) y2.Mul(y2, x) threeX := new({{.Element}}).Add(x, x) threeX.Add(threeX, x) y2.Sub(y2, threeX) return y2.Add(y2, {{.p}}B()) } func {{.p}}CheckOnCurve(x, y *{{.Element}}) error { // y² = x³ - 3x + b rhs := {{.p}}Polynomial(new({{.Element}}), x) lhs := ne...

    /*
     * For an explanation of the basic principle behind this check, see
     * https://stackoverflow.com/a/35754308/28465
     *
     * In that explanation's notation, our `overlap` check would be `x1 < y2 && y1 < x2`. We've
     * flipped one part of the check so that we're using "less than" in both cases (rather than a
     * mix of "less than" and "greater than"). We've also switched to "strictly less than" rather