

You win the public vote when you get 51% of all the people who had the right to vote. That includes those who didn’t vote.
If participation is only 50% of the voters, and you get 51% of that participation, you didn’t get 51% of the votes, you got 25.5% of the votes.
And by this, I don’t mean what the current laws consider “winning the public vote” in any particular country. I mean what they need to be for that to be really true.
My comment wasn’t about how the current laws of Austria are but about how they ought to be in any country.