This question already has an answer here:
Is there at all a way to make underscores and carets persistent in LaTeX math mode? What I mean, is to be able to write several-character sub/superscripts without using curly brackets. Could LaTeX maybe understand that a white space determines the end of my sub/superscript?
A quick example. I'd like to have something like
Compile to the same result as
I understand that this is probably not a really reliable thing, but I'm looking to take notes faster during class!