“If and Only If” Should Be Spelled “Ifeff”

If and only if is an important logical concept, useful in many contexts, both mathematical and nonmathematical. Unfortunately, “if and only if” is also an unwieldy five-syllable phrase. Mathematicians have solved this problem by shortening it to “iff”. Unfortunately, this shortening has not caught on in non-mathematical contexts. This makes some communication and thinking unwieldy and ambiguous.

I think the reason “iff” hasn’t caught on more broadly is because it’s easily misread as “if”, and doesn’t have an intuitive pronunciation. I think both of these problems would be solved by changing the spelling to “ifeff” (prononunced /​ɪfɛff/​). The etymology is that you take “iff”, and pronounce the second “f” separately. This would slightly improve the thinking and communication of most English speakers.

I think a small group of people using “ifeff” in their writing would likely start a process where “ifeff” eventually takes over, via the usual process by which vocabulary spreads, and that “ifeff” would be used by groups that don’t currently have a short-enough word for this concept. I also think the correspondence between “iff” and “ifeff” is intuitive enough that this will not cause very much confusion.