How to address reading courses in cv for Phd application for pure math?
It would be helpful to list the topics you looked at, and their sources. Even "standard" courses, with standard names, vary wildly depending on the choice of textbook or other sources, and depending on the instructor (who may be the author of notes or textbook for the course!) 

Similarly, "reading course in X" tells far too little, just as saying "standard course in X" would. Prior to the enforced uniformization of applications to our grad program, as occasional Dir of Grad Studies in Math, I required applicants to not only tell the course name, but also, even more importantly, the (title and) author(s) of the text(s)/source(s) for the course. Reading courses treated the same way.

To repeat: the standard catch-phrases/labels of course names absolutely do not describe the content... so, yes, please do give more details. These details are not at all implied by the general, vague, cliched titles.