Metamath Proof Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > MPE Home > Th. List > df-fac | Structured version Visualization version Unicode version |
Description: Define the factorial function on nonnegative integers. For example, because (ex-fac 27308). In the literature, the factorial function is written as a postscript exclamation point. (Contributed by NM, 2-Dec-2004.) |
Ref | Expression |
---|---|
df-fac |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cfa 13060 | . 2 | |
2 | cc0 9936 | . . . . 5 | |
3 | c1 9937 | . . . . 5 | |
4 | 2, 3 | cop 4183 | . . . 4 |
5 | 4 | csn 4177 | . . 3 |
6 | cmul 9941 | . . . 4 | |
7 | cid 5023 | . . . 4 | |
8 | 6, 7, 3 | cseq 12801 | . . 3 |
9 | 5, 8 | cun 3572 | . 2 |
10 | 1, 9 | wceq 1483 | 1 |
Colors of variables: wff setvar class |
This definition is referenced by: facnn 13062 fac0 13063 |
Copyright terms: Public domain | W3C validator |