FOM: relevance and v-Elim
sazonov at logic.botik.ru
Thu Nov 20 03:31:51 EST 1997
A small addition to discussion by Jon Barwise and Neil Tennant on
"the rule of v-Elim (proof by cases) so that if one case leads
to absurdity then the conclusion of the other case can be brought down
as the main conclusion".
I use this natural rule in lectures for students to show that
(A=>B) <=> (~AVB) and that (falsity=>anything) because direct
postulating these lows of classical logic seems rather artificial
for the beginners.
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