  Marian Kupczynski(MK)is the author of a controversial paper published (2020)
in the journal Frontiers in Physics. The work is built around a mathematical
claim by MK which is actually false, and MK's logical reasoning around his
claim is also incorrect. The same claim was made by him in several other recent
papers published in other journals. A proof that the claimed result is false is
the main content of our present "Comment". It is purely a mathematical
counter-example to a mathematical claim in a number of MK's papers.
