At: fun  enumer 1 2 1 1 1
1. n: 
2. m: 
3. 0 < m
4. f: (
(m-1)

n)

(n
m-1)
5. Bij(
(m-1)

n; 
(n
m-1); f)
6. n = 0
 
 Bij(
m

n; 
(n
m); 
z.z(0))
By: 
Unfold `biject` 0
THEN
Analyze 0
Generated subgoals:| 1 |    Inj( m   n;  (n m);  z.z(0)) | 
| 2 |    Surj( m   n;  (n m);  z.z(0)) | 
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