Description: gcdOLD ( A , B ) is the largest positive integer that evenly divides both A and B . (Contributed by Jeff Hoffman, 17-Jun-2008) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | df-gcdOLD | |- gcdOLD ( A , B ) = sup ( { x e. NN | ( ( A / x ) e. NN /\ ( B / x ) e. NN ) } , NN , < ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
0 | cA | |- A |
|
1 | cB | |- B |
|
2 | 0 1 | cgcdOLD | |- gcdOLD ( A , B ) |
3 | vx | |- x |
|
4 | cn | |- NN |
|
5 | cdiv | |- / |
|
6 | 3 | cv | |- x |
7 | 0 6 5 | co | |- ( A / x ) |
8 | 7 4 | wcel | |- ( A / x ) e. NN |
9 | 1 6 5 | co | |- ( B / x ) |
10 | 9 4 | wcel | |- ( B / x ) e. NN |
11 | 8 10 | wa | |- ( ( A / x ) e. NN /\ ( B / x ) e. NN ) |
12 | 11 3 4 | crab | |- { x e. NN | ( ( A / x ) e. NN /\ ( B / x ) e. NN ) } |
13 | clt | |- < |
|
14 | 12 4 13 | csup | |- sup ( { x e. NN | ( ( A / x ) e. NN /\ ( B / x ) e. NN ) } , NN , < ) |
15 | 2 14 | wceq | |- gcdOLD ( A , B ) = sup ( { x e. NN | ( ( A / x ) e. NN /\ ( B / x ) e. NN ) } , NN , < ) |