“…For this reason, more recently, some authors studied problem () trying to drop the
condition. For instance, we refer the interested readers to [
18, 19] for the
‐Laplacian equation, [
20–22] for the
‐biharmonic equation, and [
23] for the
‐triharmonic equation. However, in literature, the only results involving the
‐polyharmonic without assuming the
condition can be found in [
24], where the authors extended condition
of [
25] to the following assumption:
- :there exist , and such that
…”