Metsis:
The use of comma is not clearly defined in Esperanto. PMEG gives only vague rules:

• en lokoj, kie povas esti nature iom paŭzi, ekz. antaŭ subfrazo (such as before ke as Flanke did)
  
• komoj estas ankaŭ uzataj inter kunligitaj ĉeffrazoj

and in lists. Ofc in mathematics you follow its rules. See also another fadeno here in Lernu.

Thanks.

I have been making a brave attempt to read Esperanto texts as much as I am able to and I have noticed that in many cases there is a comma before ke in places where the comma seems wholly unnatural and unnecessary. It's confusing and jarring, and I have wondered if putting a comma in these instances is essential according to some Esperanto rule or would it still be grammatically correct to leave it out.