1 Publisher Correction to: SN Partial Differ. Equ. Appl. https://doi.org/10.1007/s42985-020-00050-y

Unfortunately systematic LaTex mistakes appeared in this article.

They all stem from failure to close braces in the LaTeX command \mathfrak{D}. The closing brace } was either left out of put in the wrong place. These mistakes render the article almost unreadable.

The original article has been corrected.