In (Friedrichs 1986, volume 1, p. 117) Lax writes "On English usage Friedrichs liked to consult his friend and colleague, Donald Flanders, a descendant of puritans and a puritan himself, with the highest standard of his own conduct, noncensorious towards others. In recognition of his moral qualities he was called Moll by his friends. When asked by Friedrichs what to name the smoothing operator, Flanders remarked that they could be named "mollifier" after himself; Friedrichs was delighted, as on other occasions, to carry this joke into print." Friedrichs, Kurt Otto (1986), Morawetz, Cathleen S. (ed.), Selecta, Contemporary Mathematicians, Boston-Basel-Stuttgart: Birkhäuser Verlag, pp. 427 (Vol. 1), pp. 608 (Vol. 2), ISBN0-8176-3270-0, Zbl0613.01020. A selection from Friedrichs' works with a biography and commentaries of David Isaacson, Fritz John, Tosio Kato, Peter Lax, Louis Nirenberg, Wolfgag Wasow, Harold Weitzner.
In (Friedrichs 1986, volume 1, p. 117) Lax writes "On English usage Friedrichs liked to consult his friend and colleague, Donald Flanders, a descendant of puritans and a puritan himself, with the highest standard of his own conduct, noncensorious towards others. In recognition of his moral qualities he was called Moll by his friends. When asked by Friedrichs what to name the smoothing operator, Flanders remarked that they could be named "mollifier" after himself; Friedrichs was delighted, as on other occasions, to carry this joke into print." Friedrichs, Kurt Otto (1986), Morawetz, Cathleen S. (ed.), Selecta, Contemporary Mathematicians, Boston-Basel-Stuttgart: Birkhäuser Verlag, pp. 427 (Vol. 1), pp. 608 (Vol. 2), ISBN0-8176-3270-0, Zbl0613.01020. A selection from Friedrichs' works with a biography and commentaries of David Isaacson, Fritz John, Tosio Kato, Peter Lax, Louis Nirenberg, Wolfgag Wasow, Harold Weitzner.