Table 1.

The truth tables of the functions $f_1^{(1)},f_2^{(1)},f_1^{(2)}$ and $f_2^{(2)}$

(x1x2)	$f_1^{(1)}$	$f_2^{(1)}$	$f_1^{(2)}$	$f_2^{(2)}$
00	1	0	0	1
01	1	1	0	1
10	0	0	0	0
11	1	1	1	0

Note that the domains of the functions $f_2^{(1)}$ and $f_2^{(2)}$ are expanded.