| Step | Hyp | Ref | Expression |
| 1 |
|
id |
_1 = l1 -> _1 = l1 |
| 2 |
1 |
anwl |
_1 = l1 /\ _2 = l2 -> _1 = l1 |
| 3 |
2 |
leneqd |
_1 = l1 /\ _2 = l2 -> len _1 = len l1 |
| 4 |
|
id |
_2 = l2 -> _2 = l2 |
| 5 |
4 |
anwr |
_1 = l1 /\ _2 = l2 -> _2 = l2 |
| 6 |
5 |
leneqd |
_1 = l1 /\ _2 = l2 -> len _2 = len l2 |
| 7 |
3, 6 |
eqeqd |
_1 = l1 /\ _2 = l2 -> (len _1 = len _2 <-> len l1 = len l2) |
| 8 |
2 |
ntheq2d |
_1 = l1 /\ _2 = l2 -> nth n _1 = nth n l1 |
| 9 |
8 |
eqeq1d |
_1 = l1 /\ _2 = l2 -> (nth n _1 = suc x <-> nth n l1 = suc x) |
| 10 |
5 |
ntheq2d |
_1 = l1 /\ _2 = l2 -> nth n _2 = nth n l2 |
| 11 |
10 |
eqeq1d |
_1 = l1 /\ _2 = l2 -> (nth n _2 = suc y <-> nth n l2 = suc y) |
| 12 |
11 |
imeq1d |
_1 = l1 /\ _2 = l2 -> (nth n _2 = suc y -> x, y e. R <-> nth n l2 = suc y -> x, y e. R) |
| 13 |
9, 12 |
imeqd |
_1 = l1 /\ _2 = l2 -> (nth n _1 = suc x -> nth n _2 = suc y -> x, y e. R <-> nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R) |
| 14 |
13 |
aleqd |
_1 = l1 /\ _2 = l2 -> (A. y (nth n _1 = suc x -> nth n _2 = suc y -> x, y e. R) <-> A. y (nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R)) |
| 15 |
14 |
aleqd |
_1 = l1 /\ _2 = l2 -> (A. x A. y (nth n _1 = suc x -> nth n _2 = suc y -> x, y e. R) <-> A. x A. y (nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R)) |
| 16 |
15 |
aleqd |
_1 = l1 /\ _2 = l2 ->
(A. n A. x A. y (nth n _1 = suc x -> nth n _2 = suc y -> x, y e. R) <-> A. n A. x A. y (nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R)) |
| 17 |
7, 16 |
aneqd |
_1 = l1 /\ _2 = l2 ->
(len _1 = len _2 /\ A. n A. x A. y (nth n _1 = suc x -> nth n _2 = suc y -> x, y e. R) <->
len l1 = len l2 /\ A. n A. x A. y (nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R)) |
| 18 |
17 |
elabed |
_1 = l1 ->
(l2 e. {_2 | len _1 = len _2 /\ A. n A. x A. y (nth n _1 = suc x -> nth n _2 = suc y -> x, y e. R)} <->
len l1 = len l2 /\ A. n A. x A. y (nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R)) |
| 19 |
18 |
elsabe |
l1, l2 e. S\ _1, {_2 | len _1 = len _2 /\ A. n A. x A. y (nth n _1 = suc x -> nth n _2 = suc y -> x, y e. R)} <->
len l1 = len l2 /\ A. n A. x A. y (nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R) |
| 20 |
19 |
conv all2 |
l1, l2 e. all2 R <-> len l1 = len l2 /\ A. n A. x A. y (nth n l1 = suc x -> nth n l2 = suc y -> x, y e. R) |