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:
“Family life is not a computer program that runs on its own; it needs continual input from everyone.”
—Neil Kurshan (20th century)
“It is unheard-of, uncivilized barbarism that any woman should still be forced to bear such monstrous torture. It should be remedied. It should be stopped. It is simply absurd that, with our modern science, painless childbirth does not exist as a matter of course.... I tremble with indignation when I think of ... the unspeakable egotism and blindness of men of science who permit such atrocities when they can be remedied.”
—Isadora Duncan (1878–1927)