[ + 1.0 ] * Sum ( h1 p2 ) * f ( h1 p2 ) * t ( p2 h1 ) [ + 0.25 ] * Sum ( h3 h4 p1 p2 ) * t ( p1 p2 h3 h4 ) * v ( h3 h4 p1 p2 ) [ + 0.5 ] * Sum ( h2 h4 p1 p3 ) * t ( p1 h2 ) * t ( p3 h4 ) * v ( h2 h4 p1 p3 )