| 1 | #u abandali |
| 2 | #a h02 |
| 3 | |
| 4 | #q q04d |
| 5 | |
| 6 | p <=> q, p & q <=> (p | q) |
| 7 | |
| 8 | #check TP |
| 9 | |
| 10 | p <=> q <-> p & q <=> (p | q) |
| 11 | |
| 12 | 1) p & q <=> (p | q) |
| 13 | 2) (p & q => p | q) & (p | q => p & q) by equiv |
| 14 | 3) (!(p & q) | p | q) & (!(p | q) | p & q) by impl * 2 |
| 15 | 4) (!p | !q | p | q) & (!(p | q) | p & q) by dm |
| 16 | 5) (true | !q | q) & (!(p | q) | p & q) by lem |
| 17 | 6) true & (!(p | q) | p & q) by simp1 |
| 18 | 7) !(p | q) | p & q by simp1 |
| 19 | 8) !p & !q | p & q by dm |
| 20 | 9) (!p & !q | p) & (!p & !q | q) by distr |
| 21 | 10) (!p | p) & (!q | p) & (!p | q) & (!q | q) by distr * 2 |
| 22 | 11) true & (!q | p) & (!p | q) & true by lem * 2 |
| 23 | 12) (!q | p) & (!p | q) by simp1 * 2 |
| 24 | 13) (q => p) & (p => q) by impl * 2 |
| 25 | 14) p <=> q by equiv |