Sorry for nitpicking, but just trying to clarify what seems like a double negative - do you mean "to affirm that equation", i.e. that the author claims they are equal?
I guess you're right, negating an inequality is likely the same as affirming an equality? I am not a native speaker.
Is that not the same logically in every language?
No, in Spanish double negations are not positive statements.
I think the parent commenter was using the word 'equation' in its colloquial sense to refer to any mathematical expression or statement, despite their statement containing a 'not equals to' symbol, rather than actually equating them (which would have an equals sign).