Discrete Structures Logic Proof Sequence Prove the validty o

Discrete Structures Logic Proof Sequence

Prove the validty of the following argument using logic proof sequence.

[[ (A -> B)\' -> C]\' -> D ] and B\' and C\' and D\' -> A\'

Inlcude the steps you took -- modus tollens, modus ponens, simplication, implication, etc.

Solution

By C\' and modus tollens applied to (A --> B)\' --> C, we have A-->B.

By B\' and modus tollens applied to A --> B, we have A.

By A and modus tollens applied to D\' --> A\', we have D.