Computer Science
Logical operators are implemented as logic gates in digital circuits. Practically all digital circuits (the major exception is DRAM) are built up from NAND, NOR, NOT, and transmission gates. NAND and NOR gates with 3 or more inputs rather than the usual 2 inputs are fairly common, although they are logically equivalent to a cascade of 2-input gates. All other operators are implemented by breaking them down into a logically equivalent combination of 2 or more of the above logic gates.
The "logical equivalence" of "NAND alone", "NOR alone", and "NOT and AND" is similar to Turing equivalence.
That fact that all truth functions can be expressed with NOR alone is demonstrated by the Apollo guidance computer.
Read more about this topic: Truth Function
Famous quotes containing the words computer and/or science:
“What, then, is the basic difference between today’s computer and an intelligent being? It is that the computer can be made to see but not to perceive. What matters here is not that the computer is without consciousness but that thus far it is incapable of the spontaneous grasp of pattern—a capacity essential to perception and intelligence.”
—Rudolf Arnheim (b. 1904)
“One science only will one genius fit;
So vast is art, so narrow human wit.”
—Alexander Pope (1688–1744)