Addendum to "Critical behavior of (2+1)-dimensional QED: 1/Nf-corrections in an arbitrary nonlocal gauge"

Dynamical chiral symmetry breaking is studied within (2 + 1)-dimensional QED with N four-component fermions. The leading and next-to-leading orders of the 1/N expansion were computed exactly by V. P. Gusynin and P. K. Pyatkovskiy [Phys. Rev. D 94, 125009 (2016)] and A. V. Kotikov and S. Teber [Phys. Rev. D 94, no. 11, 114011 (2016)] in an arbitrary nonlocal gauge. In this addendum to the work by Kotikov and Teber, we show that the resummation of the wave-function renormalization constant at the level of the gap equation yields a complete cancellation of the gauge dependence of the critical fermion flavour number resulting in N-c = 2.8469, which is such that dynamical chiral symmetry breaking takes place for N < N-c. The result is in full agreement with one of Gusynin and Pyatkovskiy.