Logic / Unit 5 Logic 199 short lesson, about 20 seconds
Addition
Captions available
The idea
From p, derive p ∨ q — for any q whatsoever.
In practice
1. A. 2. A ∨ Z (1, Add).
Where people slip
It feels like cheating. It isn't: a disjunction with one true disjunct is true, whatever rides along. Its main use is building the exact disjunction a later rule needs.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
- Nothing yet depends on this.
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