  We solve the Schwinger-Dyson equations for (2+1)-dimensional QED in the
presence of a strong external magnetic field. The calculation is done at finite
temperature and the fermionic self energy is not supposed to be
momentum-independent, which is the usual simplification in such calculations.
The phase diagram in the temperature-magnetic field plane is determined. For
intermediate magnetic fields the critical temperature turns out to have a
square root dependence on the magnetic field, but for very strong magnetic
fields it approaches a B-independent limiting value.
