In addition to the logical operations defined here – computer scientists have defined two other operations (which are merely abstractions of operations defined in my previous article) since they are used so often. They are NAND and NOR, symbolically ↑ (|) and ↓ (⊥). I say they are abstractions because they are simply the negation of AND and OR operations
NAND
| A | B | A AND B | NOT (A AND B) | A NAND B |
| 1 | 1 | 1 | 0 | 0 |
| 1 | 0 | 0 | 1 | 1 |
| 0 | 1 | 0 | 1 | 1 |
| 0 | 0 | 0 | 1 | 1 |
NOR
| A | B | A OR B | NOT (A OR B) | A NOR B |
| 1 | 1 | 1 | 0 | 0 |
| 1 | 0 | 1 | 0 | 0 |
| 0 | 1 | 1 | 0 | 0 |
| 0 | 0 | 0 | 1 | 1 |
13. August 2009
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