Rewrite the equations on page B-44 for a carry-lookahead logic for a 16-bit adder using a new notation. First, use the names for the CarryIn signals of the individual bits of the adder. That is, use c4, c8, c12, … instead of C1, C2, C3, …. In addition, let Pi,j; mean a propagate signal for bits i to j, and Gi,j; mean a generate signal for bits i to j. For example, the equation 

C2  = G1 + (P1 · G0) + (P1 · P0 · c0) 

can be rewritten as

c8 = G_7,4 + (P_7,4 · G3,0) + (P_7,4 · P3,0 · c0).

This more general notation is useful in creating wider adders.