At: lang sing prod 1 2 1 2 1 1 2 1 1 2 1 1
1. Alph: Type
2. L: Alph*
Prop
3. l: Alph*
4. L(l)
5. ||l[0..0
]|| = 0
6. m: Alph*
7. u: Alph
8. v: Alph*
9. ||v|| = 0 
v = nil
10. ||v||+1 = 0
u.v = nil
By: Inst
Thm* 
l:A*. ||l||
0
[Alph;v]
Generated subgoals:None
About:
