Двойное отрицание:
((x3 ∧ x1) ∨ (x1 ∧ x3) ∨ (x4 ∧ x4)) =¬(¬((x3 ∧ x1) ∨ (x1 ∧ x3) ∨ (x4 ∧ x4))) =¬(¬(x3 ∧ x1) ∧ ¬(x1 ∧ x3) ∧ ¬(x4 ∧ x4)) =¬(¬x3 ∨ ¬x1) ∧ ¬(¬x1 ∨ ¬x3) ∧ ¬(¬x4 ∨ ¬x4) =(x3 ∨ x1) ∧ (x1 ∨ x3) ∧ (x4 ∧ x4) =(x1 ∨ x3 ∨ x4).
Обобщённый закон де Моргана:
(x1 ∨ x3 ∨ x4) =¬(¬(x1 ∨ x3 ∨ x4)) =¬(¬x1 ∧ ¬x3 ∧ ¬x4) =(x1 ∧ x3 ∧ x4).
Двойное отрицание:
((x3 ∧ x1) ∨ (x1 ∧ x3) ∨ (x4 ∧ x4)) =
¬(¬((x3 ∧ x1) ∨ (x1 ∧ x3) ∨ (x4 ∧ x4))) =
¬(¬(x3 ∧ x1) ∧ ¬(x1 ∧ x3) ∧ ¬(x4 ∧ x4)) =
¬(¬x3 ∨ ¬x1) ∧ ¬(¬x1 ∨ ¬x3) ∧ ¬(¬x4 ∨ ¬x4) =
(x3 ∨ x1) ∧ (x1 ∨ x3) ∧ (x4 ∧ x4) =
(x1 ∨ x3 ∨ x4).
Обобщённый закон де Моргана:
(x1 ∨ x3 ∨ x4) =
¬(¬(x1 ∨ x3 ∨ x4)) =
¬(¬x1 ∧ ¬x3 ∧ ¬x4) =
(x1 ∧ x3 ∧ x4).