Disprove or

From CS2800 wiki


To disprove "[math]P [/math] or [math]Q [/math]", you must both disprove [math]P [/math] and disprove [math]Q [/math]. Put another way, the logical negation of "[math]P [/math] or [math]Q [/math]" is "not [math]P [/math] and not [math]Q [/math]".