Can someone provide a formal definition of addition for the natural numbers directly from the axioms of ZFC? If this can't be done, why not?

  • $\begingroup$ Addition of what? $\endgroup$ – drhab Nov 14 '19 at 12:59
  • $\begingroup$ Natual numbers. Sorry, meant to type that. $\endgroup$ – Jacob Hulse Nov 14 '19 at 13:00
  • $\begingroup$ Among many other places to find this, see Enderton's Elements of Set Theory. $\endgroup$ – Dave L. Renfro Nov 14 '19 at 13:00