I'm going to go out on a limb here and say that those are Gygax's notes, not Arneson's. Notice how, in the bottom left, they're all tagged as "DEFT'S EXH" and a number? That looks a lot like "defendant's exhibit." And the date for each is 7-18-79, which means they're part of the infamous Arneson v. Gygax case, where Gygax was the defendant.
Now, strictly speaking, that just establishes that these are exhibits put forward by Gygax in the case...but I find it hard to believe that he'd be putting forward exhibits that establish Arneson as having been the creative mind behind various aspects of the game. Hence my presumption that these are Gygax's notes.