I'm confused with the selected part and generally with the word waive in this context.
Whether it is:
a) 90% chose to ignore Article 20?
b) 90% refused to take a notice about the meeting?

Notwithstanding Article 20, a meeting of members held in contravention of the requirement to give notice is valid if members holding a ninety (90) percent majority of the total voting rights on all the matters to be considered at the meeting have waived notice of the meeting and, for this purpose, the presence of a member at the meeting shall be deemed to constitute waiver on his part.

(Article 20 says that a notice must be issued to each member minimum 7 days before the meeting).

And a bonus question whether is it:
a) to waive = to refuse generally of smth? or
b) to waive = to give up a right?

Thanks in advance.