How do mathematicians recognize the article entitled "On the Nature of Some Euler's Double Equations Equivalent to Fermat's Last Theorem", published in Mathematics, Volume 10, Issue 23 (December-1 2022) by MDPI?
it seems that you don't understand much about classical Diophantine analysis.
However, the article on MDPI was approved by a prestigious Academic Editor, such as Prof. Abdelmejid Bayad, whose CV is easily found on the Internet.
Not only has the article been marked with "Feature" and the Journal Mathematics by MDPI is classified in SCOPUS !!!
I therefore invite you to carefully read the article that Ossicini has made available in order to clarify why the proof he uses is valid and how it can refer specifically to Fermat.
Attached you will find the above article.
Happy reading and I hope you have the humility to study it, to even challenge it, but with appropriate observations.
Dear Pietro Lacroux, the journal Mathematics (MDPI) has published an Expression of Concern in regard to Ossicini's paper. Please, see https://www.mdpi.com/search?journal=mathematics&article_type=expression-of-concern.
"With this notice, the Mathematics Editorial Office states its awareness of concerns regarding the findings of the published manuscript [1]. Concerns have been raised by readers about the validity and accuracy of the results. In order to maintain the highest scientific standards, the Editorial Office has decided to issue this expression of concern while an investigation is conducted.
The author of this publication has been contacted for further clarification. The investigation is being coordinated by the Editorial Board and Editor-in-Chief. An update will be provided following the conclusion of the investigation."
The author has already produced and sent a note that clarifies all the issues relating to his work.
Let's give the right amount of time (we hope it doesn't exceed more than three months) to the editorial committee of the magazine to complete its investigation in the best possible way.