# Name for three-valued sign $+, -, 0$

Is there an accepted term (an adjective or prefix) like strict, trichotomous, strong or definite sign to indicate the three-valued sign whose values are $+$, $-$, and $0$?

Are there words reserved for this use in mathematical languages besides English?

An example is functions or differential equation solutions that do not change "sgn". So to speak.

Edit. The phrase should retain the word "sign" and add to it an adjective, prefix or (less likely) a suffix. So, "super-sign (it)" is hypothetically a candidate, but not necessarily signito, sssignnnn, signulus, signifier, signiance, signplusplus.

• English is not a mathematical language. There is mathematical notation. There are human natural languages, one of which is English. Mathematical notation is more likely to be understood by speakers of any language. For example, even though some notation uses Greek letters, that doesn't mean it is more or less understandable to those who do or don't understand the Greek language. Jun 1, 2013 at 14:35
• @FeralOink, there is mathematical English, and I was asking about mathematical X, where X runs over the non-English languages, but the difference between (mathematical (languages besides English)) and ((mathematical languages) besides English) is another thing that does not have a completely natural expression given the difficulty of simulating parentheses. Maybe "mathematical vocabulary of languages other than English".
– zyx
Jun 2, 2013 at 3:02
• Much better! This: mathematical vocabulary of languages other than English is a fine way to express that which you seek. The SE site that indicates my expertise most clearly is English EL&U SE. So I do have some credibility ;o) maybe ;o) Jun 2, 2013 at 3:06

## 1 Answer

The signum function meets your criteria.

• It does not, which is the reason that I wrote this function into the question. Also, I do not know how to pronounce it when speaking (sgn, that is). Really I am looking for an understandable adjective to say before the word "sign". Thanks for the answer, in any case.
– zyx
May 23, 2013 at 18:50
• @zyx, it is hard to come up with an argument that "signum" doesn't contain the word "sign". May 23, 2013 at 19:51
• @zyx, You're probably right that "does not change signum" might not be clear to all mathematical audiences. It would be much better to use clear words as in "every solution is either strictly positive, constantly zero, or strictly negative". I don't think there is an adjective you can put in front of sign to represent this meaning clearly in English. May 24, 2013 at 2:06
• Heaviside was the other function that crossed my mind too, regarding an answer to this question! I thought about it for about 30 minutes today, if I could answer with something meaningful, satisfying your criteria, but failed to find an answer. I like the question very much! I found a concept (and name) that is almost suitable, in computing. Computing is not mathematics, alas. Jun 2, 2013 at 3:29
• @FeralOink, on Wikipedia there is an entry for "three-valued comparison" in computer science which is quite close.
– zyx
Jun 2, 2013 at 3:33