QED symbol at the end of a proof

[gdietl]

In the proof environment of bookdown, the end has been marked by a square, commonly used as the QED symbol. However, using quarto, the end of the proof is not specified. Is there an easy way to add this symbol to the proof environment?

[cderv]

I think we should add it by default yes. We can probably port what we did in bookdown. Thanks ! I'll create an issue

[ghost]

Thanks @cderv moved to #5036