Under the condominium act a general meeting is quorate if co-owners holding more than half of the ownership shares are present, either in person or through an authorised representative. It is not the headcount but the represented ownership share that counts.
Quorum must be established not once at the start but before the vote on each agenda item, because owners may leave during a long meeting and a later item may no longer have the required share.
If the meeting is not quorate, the law allows a repeated meeting with milder conditions, which in practice is the most frequently used solution after an unsuccessful first convocation.
A practical tip: the validity of proxies should be checked at registration, because a formally flawed proxy can later call into question the establishment of quorum and thereby the validity of every decision taken.
It is also important to know that adopting a given agenda item often requires a qualified majority beyond quorum, where the bylaws or the law prescribe it, for example for registering a mortgage or a major investment.
Merbo documents the present ownership share item by item at every general meeting so that no doubt can arise afterwards about the validity of a resolution.
To improve turnout it is worth indicating in the invitation which agenda items need a qualified majority, as this encourages owners to send a proxy rather than simply staying away.