I received a reply from the author, Andrea Sfiligoi, as follows:"From: Andrea Sfiligoi Sent: Mon, May 9, 2016 2:57 pmThanks! All gray areas will be clarified in the next update of the pdf, currently with a proofreader.

I received a reply from the author, Andrea Sfiligoi, as follows:"From: Andrea Sfiligoi Sent: Mon, May 9, 2016 2:57 pmThanks! All gray areas will be clarified in the next update of the pdf, currently with a proofreader.