Did the AMS pay for any of TeX?
Yes: I do not know any details about who payed for what; I guess
barbara beeton is the "honorary official historian"?
(well, i was hoping to stay out of this, but chris doesn't give
me much choice.)
ams funded the development of ams-tex, ams-latex, and various fonts.
ams has also had one or more staff members highly trained in tex
macro development continuously since 1979, and at times, also a
metafont technician. ams is part of (and organizer of) the
consortium that arranged for the release of the blue sky cm type 1
fonts. ams also instigated the founding of tug, and provided staff
and office space for the first couple of years; tug had become
fiscally separate from ams by 1982, i believe.
i can't say that any of this (with the possible exception of the
ams-tex development and participation in the font consortium) is
direct support of "tex", in the sense that sebastian meant, but
is contingent on what ams considers its own self interest in
obtaining ready-to-publish math manuscripts. certainly ams
hasn't, and isn't prepared to, fund tex development to the same
degree that some commercial organization would fund a potentially
profitable product, and wouldn't even if there were no such