Boolean functions: sum of products
	Example: majority function
		Inputs: 3			Output: 1 whenever more than half of the inputs are true.
		a	b	c	z		Minterms
		0	0	0	0
		0	0	1	0
		0	1	0	0
		0	1	1	1		\abc
		1	0	0	0
		1	0	1	1		a\bc
		1	1	0	1		ab\c
		1	1	1	1		abc
		z = \abc + a\bc + ab\c + abc