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Diffstat (limited to 'examples/systemS/ex4eng.txt')
| -rw-r--r-- | examples/systemS/ex4eng.txt | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/examples/systemS/ex4eng.txt b/examples/systemS/ex4eng.txt deleted file mode 100644 index 3ad4f3549..000000000 --- a/examples/systemS/ex4eng.txt +++ /dev/null @@ -1,8 +0,0 @@ -We will show that (A -> B) v (B -> A). -To that end, we will assume ~ ((A -> B) v (B -> A)) and show _|_. -So let us assume that ~ ((A -> B) v (B -> A)). -Then, by the first de Morgan's law, we get ~ (A -> B) & ~ (B -> A) to prove _|_. -So by splitting we get ~ (A -> B), ~ (B -> A) to prove _|_. -By implication negation, we get A, ~ (B -> A) to prove _|_. -By implication negation, we get A, ~ A to prove _|_. -Hence we get _|_ as desired. |