olemus
(a) väitele vastupidine väide kontekstist sõltuvas tähenduses
= a statement opposite to a statement in a context-dependent sense
https://plato.stanford.edu/entries/negation/
https://en.wikipedia.org/wiki/Affirmation_and_negation
https://en.wikipedia.org/wiki/Negation

(b) Boole'i tehe: loogiline täiend
= the process of reversing the meaning of a Boolean expression
https://mathworld.wolfram.com/Negation.html
https://www.bouraspage.com/repository/algorithmic-thinking/how-to-negate-boolean-expressions