What is the odd inequality sign I saw in my lecture notes?

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    Inequality Sign
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The discussion centers on an unusual mathematical symbol resembling a greater-than sign over a less-than sign, which participants interpret as "is not equal to." Several possible names for this symbol are suggested, including \lessgtr, \gtrless, and others. The consensus leans towards it representing a relationship where values can be either less than or greater than, often used in specific contexts. It is noted that this symbol is rarely used, with more common practices involving separate lines for different cases. Overall, the symbol signifies a nuanced comparison rather than a straightforward equality.
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I saw this rather odd symbol of the the greater sign on top of the less sign in my lecture notes. I am wondering if there is a name for this symbol and if signifies 'equal to' as well?
 
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I would interpret that as "is not equal to".
 
Is it any of these?

\lessgtr, \quad<br /> \gtrless,\quad<br /> \lesseqgtr,\quad<br /> \gtreqless,\quad<br /> \lesseqqgtr,\quad<br /> \gtreqqless
 
Dr. Seafood said:
Is it any of these?

\lessgtr, \quad<br /> \gtrless,\quad<br /> \lesseqgtr,\quad<br /> \gtreqless,\quad<br /> \lesseqqgtr,\quad<br /> \gtreqqless

I'd say it'd probably be the second one.
 
Again, my best guess is "is not equal to".
 
It's an abbreviation of < or >, the alternatives being explained or elaborated on nearby.

You could write: a≶b≶c, which means that either a<b<c or a>b>c.
Or you could write something like: |x|=±x if x≷0.
The upper level is one case, the lower level is the other case.

It is rarely used. Different cases are usually put on different lines with braced conditions.
 
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