Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > ILE Home > Th. List > df-fac | Unicode version |
Description: Define the factorial function on nonnegative integers. For example, because (ex-fac 13684). 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 10646 | . 2 | |
2 | cc0 7761 | . . . . 5 | |
3 | c1 7762 | . . . . 5 | |
4 | 2, 3 | cop 3584 | . . . 4 |
5 | 4 | csn 3581 | . . 3 |
6 | cmul 7766 | . . . 4 | |
7 | cid 4271 | . . . 4 | |
8 | 6, 7, 3 | cseq 10388 | . . 3 |
9 | 5, 8 | cun 3119 | . 2 |
10 | 1, 9 | wceq 1348 | 1 |
Colors of variables: wff set class |
This definition is referenced by: facnn 10648 fac0 10649 |
Copyright terms: Public domain | W3C validator |