Hello, GRIM!

I don't know if this is the best way, but . . .

I use (Alternate Defintion of Implication) for: .What is the best way to approach a proof based on contradiction

for the proposition: .

Begin with the negation of the proposition:

. . . . . . . . . . . [1]

. . . . . . . . . . ADI

. . . . . . . . ADI

. . . . DeMorgan

. . . . . . . . . .DeMorgan

. . . . . . . . . . Associative

. . . . . . . . . . DeMorgan

. . . . . . . . . . . DeMorgan

We have a statementits negation . . . This is always false.and

Hence, our negation [1] is false

. . and the original proposition is true.