“…[BHL + 15, BHY15, BKW15, DLM + 03, Fol14, Gol14, HJL15, HL17, HK14, KL12, KPP, Mün13, Woj, Web10], there is an upcoming interest in non-linear problems. On the one hand this concerns non-linear operators such as the p-Laplacian, [HM15, KM16,Mug13], and on the other hand non-linear equations such as the Kazdan-Warner equation [GLY16,Ge17].…”