Classical logic embeds in intuitionistic logic by Gödel–Gentzen see https://en.m.wikipedia.org/wiki/Double-negation_translation https://en.m.wikipedia.org/wiki/

Classical logic embeds in intuitionistic logic by Gödel–Gentzen see https://en.m.wikipedia.org/wiki/Double-negation_translation https://en.m.wikipedia.org/wiki/Double-negation_translation