- Triple bar
"For the horse jump, see
Oxer "The triple bar, ≡, is a symbol used in formal
logic . It has the appearance of a "=" sign with a third line.Logically, it has a similar meaning to the if and only if coupler ⇔. However, in some texts ⇔ is used as a symbol in logic formulas, while ≡ is for reasoning about those formulas (as in
metalogic ).In addition, it has the completely separate meaning of modular equivalence in number theory: we write a equiv b pmod N if "N" divides "a" − "b".
This symbol is also used when it appears in an equation which is a definition of its
left-hand side .It is also used for "identical equality" of functions; one writes f equiv g for two functions "f", "g" if we have f(x) = g(x) for all "x".
It is
Unicode character 8801. TheHTML entity ≡ also corresponds to the triple bar.
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