To prove two sentences logically equivalent, one must show that from the first as premise, the second can be derived as conclusion. We have started with these two: "All tigers are carnivores" is symbolized as '(^x)(Tx>Cx)' and No tigers are non-carnivores" is symbolized as '~(%x)(Tx&~Cx)' In tutorial 7.2 we showed did one "half" of a proof for the equivalence of obversion. You do the other: Show the other. You may use the standard PD. (For instance, you can type '^x' or 'Vx' instead of '(^x)'.) Selected answers are available. And the new rules are here. |