Logic / Unit 5 Logic 213 short lesson, about 20 seconds
Tautology (Redundancy)
Captions available
The idea
p :: p ∨ p, and p :: p · p.
In practice
Repetition adds nothing and can be collapsed — or manufactured.
Where people slip
Mostly used at the end of dilemma proofs, collapsing q ∨ q into q. Blink and you'll miss needing it.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
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