Functional Dependencies
A mathematical function maps an input to a single output.
Examples
f(x) = 2x - 1 |
f(x, y) = (x div y, x mod y) |
| x |
2x - 1 |
| 87 |
173 |
| -10 |
-21 |
| 5 |
9 |
| 0 |
-1 |
|
| x |
y |
x div y |
x mod y |
| 25 |
3 |
8 |
1 |
| 91 |
17 |
5 |
6 |
| -19 |
4 |
-5 |
1 |
| 14 |
7 |
2 |
0 |
|
Counter-examples
- : Yields a different number each time it is
called (modulo some large number).
- sqrt(9) is both 3 and -3.
-
|