I saw a Tuple Relational Calculus formula, and it contained the symbol <>.
What does it mean?
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4My relational calculus is extremely sketchy but isn't that just a "not equals"?– Martin SmithDec 29, 2013 at 1:45
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Why are images of text, code and mathematical expressions discouraged?– philipxyFeb 19 at 18:16
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2 Answers
As Martin said, this means "not equals"
<> is not defined in relational calculus (or anywhere in math). It however is often used in programming languages (like SQL) to express "not equal". The correct sign would be the equal sign with a vertical line through its center. (= and | on top of each other).
answered Dec 29, 2013 at 15:23
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1I haven't seen
<>in a math textbook but if it was used, it would probably mean "less than or greater than" which is not exactly the same as!=or≠(not equal). Unless the domain of possible values is totally ordered. Dec 29, 2013 at 22:05