[tex-hyphen] hyphenation with ligatures in input

[bnb at ams.org]

Arthur says

      In American English "Xnancial" is hyphenated as "X-nan-cial".  In
    British English it's hyphenated as "Xn-an-cial".  Hence "?-nan-cial" and
    "?n-an-cial", respectively.

in u.s. english, no it's not, because
\lefthyphenmin=2 .  to demonstrate:

  *\showhyphens{iconography}

  Underfull \hbox (badness 10000) detected at line 0
  [] \tenrm iconog-ra-phy

  *\lefthyphenmin=1

  *\showhyphens{iconography}

  Underfull \hbox (badness 10000) detected at line 0
  [] \tenrm i-conog-ra-phy

(and a hyphen that ought to be there,
before the "n", is missing.  into the
exception list that goes.)
						-- bb