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
		This can be simplified:
		z = \abc + a\bc + ab (\c + c)
		= \abc + a\bc + ab
		= \abc + a\bc + ab + abc					Why?
		= bc(a + \a) + a\bc + ab
		= bc + a\bc + ab + abc
		= bc + ac(\b + b) + ab
		= bc + ac + ab