if I could be a researcher, this would be one of my main topics. I have personal reasons to be interested in languages with alphabets that have "very special sy

if I could be a researcher, this would be one of my main topics. I have personal reasons to be interested in languages with alphabets that have "very special symbols" such as the parenthesis. in general, i'm curious about how as you progress up the type language hierarchy it becomes necessary to keep adding specialized symbols to keep up. most interestingly, i wonder about how one pair of symbols (open and close) add a lot of expressive power but I suspect adding more different types of pairs of symbols won't significantly augment the expressiveness but I don't know for sure. this is also reminiscent of dyck languages and their corresponding automata, which can recognize and match open and closing parenthesis. I did not know visibly push down was sufficient to recognize parenthesis, I thought a stack was sufficient. but given a stack is more powerful than the unidirectional "stack" of a VPLs it all makes sense