One thing to note is that there is no universally agreed upon convention for denoting math objects. Textbook and research paper start with a section on notation to clarify the symbols they will use. Notation often varies between fields, academic schools, and sometimes there are even differences between the notation you would use when writing on a blackboard vs. the notation you would use in print.
That being said, for the most basic concepts the notation is pretty consistent so if you skim through one or two books you'll be able to get the feel for it. Understanding the actual math—that will take longer.
"One thing to note is that there is no universally agreed upon convention for denoting math objects."
This is the thing that trips me up most often. It's especially a problem when the author believes that their notation and variables are universal and therefore don't need to be defined. I've spent a lot of time these past few months trying to "reverse engineer" calculations done in research papers to verify their notation.
Textbooks and theses generally do a better job of defining everything because they aren't as concerned about document length.
I think the reason is that math notation is used in context. Which is what explains the two different notations for calculus derivatives. They were interested in different things! Similarly in quantum mechanics (not my area) you may want to use bra-ket notation or matrix representations if you care about implementation details.
Usually notations that have been here for a while are quite stable, but can still diverse depending on countries. For example in France you would write [2, 5[ for the range of real numbers between 2 included and 5 excluded, but in the US it's more common to see [2, 5)
Notations that are more recent are... all over the place.
But as parent said, good papers will always include a notation section to disambiguate. Bad papers won't.
That being said, for the most basic concepts the notation is pretty consistent so if you skim through one or two books you'll be able to get the feel for it. Understanding the actual math—that will take longer.
As for references, here is a very comprehensive standard, ISO 80000-2 that defines recommendations for many of the math symbols, with mentions of other variations: https://people.engr.ncsu.edu/jwilson/files/mathsigns.pdf#pag...
For something shorter (and less complete), you can also check the notation appendices in my books: https://minireference.com/static/excerpts/noBSguide_v5_previ... https://minireference.com/static/excerpts/noBSguide2LA_previ...