Greetings!
My understanding of the single-word switch indicator is that it is to be used whenever a single word occurs between two math expressions. The only other option would be to go in and out of Nemeth around the word.
A colleague has interpreted the Guidance use of the word "may" in "when a single word standing alone occurs between two math expressions, a single-word switch indicator MAY be used ..." [emphasis added] to mean that instead of using the single-word switch indicator we can simply spell the word out uncontracted, if there are any contractions, and stay in Nemeth. I think that interpretation is ignoring the beginning of the sentence: "To avoid use of switch indicators ..." meaning open/close Nemeth.
Clarification would be appreciated.
Thanks,
Shelley Mack