Thanks, Paul, but that's what I've been able to do on my own. The characters "mod" should not be italicized, just as "sin, cos", etc. are not italicized for the trigonometric functions.

If I right-click on the word "mod" in what you've sent me, a context menu comes up offering me the chance to alter the font. When I select "font" from this menu and select "regular" instead of "italic", which is already highlighted, there is no change to the appearance of the word "mod" in the equation. If there were, that would solve my problem.

Maybe there's something among the unicode symbols for writing equations that will help me out. I haven't looked.

Thanks again.