First of all I find it disturbing that the is an element of symbol wasnt showing up for JKeck since there seems to be nothing irregular about the way it was entered looks like it came from the Math and logic collection in the rolldown menu from the edit pages which gives  If you have this problems you are probably missing loads of symbols in math articles since this is the privileged way to represent them You could try to replace the symbol by  giving  or by clicking on the symbol in Math and logic yourself which might resolve some coding issue to see it that works better TeX code in WP produces images which avoids such problems but looks bad in inline formulas however much the formulas themselves are of superior quality If this is really a problem of your local installation the solution cannot be to change the WP articles  As for problems understanding I think you really dont need to understand the axiom of choice unless you are a mathematician interested in foundations In physics you will never come about a situation where a result depends on the axiom of choice because it talks about provability in set theory only Probably the opening sentence should make this clear For any reasonable collection of nonempty sets one could encounter in real life a choice function is easily found without use of axioms and this is the reason that the axiom seems reasonable but in mathematics it gets applied in highly abstract and complicated situations where the real world justification for the existence of choice functions no longer suffices