Thanks.
Unfortunately, there is no way. In the first place, he has honestly no knowledge of the subject. He just chooses random topics, and then he does his best to hide his references. For example, he would convert some PDF file into a presentation and then put his own name at the start. But mostly in the past I was able to track those sources using the google. Actually that day when I started this thread I spent almost more than two hours trying to find the presentation he had used. Mostly he uses
these notes to create his presentations
Now I'm particularly focused on the Section 4. I don't know why but I think it uses the array method and as you said the solution looks correct to you. If it still doesn't make any sense then I don't think we can do much about it. Thanks a lot.
Regards
PG