Extending matchings in planar graphs IV

Abstract The structure of certain non-2-extendable planar graphs is studied first. In particular, 4-connected 5-regular planar graphs which are not 2-extendable are investigated and examples of these are presented. It is then proved that all 5-connected even planar graphs are 2-extendable. Finally, a certain configuration called a generalized butterfly is defined and it is shown that 4-connected maximal planar even graphs which contain no generalized butterfly are 2-extendable.