When reading publications, I find really hard to understand those math formulas/functions.
Seems like each paper uses its own notation with different symbols and syntax.
In particular some mixed calculus/set-theory where are used their own definitions which are too convoluted to remember.
When I find myself reading a calculus formula, I already forget the notations for each symbol and basically see a bunch of meaningless letters and brackets.
If someone wrote a paper, it should be possible to understand it but why is it so hard to remember the notations?