Can someone explain how in propositional logic these are equivalent :
A ∧ B ∧ (¬B ∨ ¬C) ≡ A ∧ B ∧ ¬C
Because using the distributive law I would get:
≡ (A ∧ B ∧ ¬B) ∨ (A ∧ B ∧ ¬C)
≡ A ∨ (A ∧ B ∧ ¬C)
≡ (A ∨ A) ∧ (A ∨ B) ∧ (A ∨ ¬C)
≡ A ∧ (A ∨ B) ∧ (A ∨ ¬C)
Hint. B ∧ ¬B is false, so what is A ∧ B ∧ ¬B ?