Is Dima Dmitry or Vadim?
Both Dima and Mitya are an abbreviation on behalf of Dmitry. Little Vadim is Vadik. This is so, well, and in people who like it - often enough Vadim called Dima, the names are consonant, so people are being. Although these are completely different names.
Dmitry, abbreviated name Dima, even Dmitriev Mitami called. Vadim is Vadik (Vadyusha, Vadya). But if Dmitry is called Vadim (and vice versa), and the man is calm about it, then why not! I, for example, on the passport Anastasia, Nastya. But I got so used to Asya's name that I probably will not respond if someone calls me so from afar.
Dima is an abbreviated name in the name of Dmitry. Sometimes Dmitriev is also called Mitya, but this is more of an outdated form of a name. Now, it's so rarely called. And I do not like Mitya at all.
And Vadim is usually called Vadik.
In general, people often confuse names. My son's name is Vitaly, he was often called Vitya, but I corrected each time, and slowly got used to it.
The first time I hear this. Yes, Dmitriev could be called both Mitya and Dimami. And on behalf of Vadim Vadik was always a diminutive name. Never heard neither I nor my mother (and it's still different generations) to Vadim called Dimami. This, apparently, is some kind of local phenomenon.
To be honest, I first hear Vadimov called Dimami. Vadim were always Vadis, and Dmitriy were Mitami, Dimami, Diman, Dimona. By the way, the Bashkirs have a very popular name Dim. In everyday life, they are also called Dimami.