I don’t understand why we’re branching out from ~R, and also, why did we put P Q instead of P R in the branch? On top of that, I also don’t get why Q branches into P AND R!!
1) (P ∨ Q) ∧ (P ∨ R) ⇔ (P ∨ Q) ∧ ~(~P ∧ ~R) ... De Morgans ∴ (P ∨ Q) and ~(~P ∧ ~R) ... ∧ deconstruction 2) (~P ∧ ~R) From 1 and 2 ~(~P ∧ ~R) is TRUE and (~P ∧ ~R) is TRUE ... this is a contradiction ∴ 1 and 2 are NOT consistent.
This one took me a bit longer to fully grasp, a lot of rewinding but i figured out everything (hopefully) so looking forward to the excercises!
This is amazing!
I'm too dumb to get it.
@@jeremiahsilva7458 Wrong.
I don’t understand why we’re branching out from ~R, and also, why did we put P Q instead of P R in the branch? On top of that, I also don’t get why Q branches into P AND R!!
In our class we call the NCD and the NDD 'The Morgan'. I quite prefer that name over this spaghetti alternative xD
📝
Where is the solution video?
1) (P ∨ Q) ∧ (P ∨ R) ⇔ (P ∨ Q) ∧ ~(~P ∧ ~R) ... De Morgans
∴ (P ∨ Q) and ~(~P ∧ ~R) ... ∧ deconstruction
2) (~P ∧ ~R)
From 1 and 2
~(~P ∧ ~R) is TRUE and (~P ∧ ~R) is TRUE ... this is a contradiction
∴ 1 and 2 are NOT consistent.