What does 'sign' mean in an equation?

Question

I'm curious what sign means in the context of mathematical notation. I'm reading a paper right now and it uses:

$$ sign \overrightarrow{\lambda} \cdot \overrightarrow{a} $$

Is that equivalent to $\pm$ ?

I've never seen this before.

Thanks.

probably signum, which is $1$ if the argument is positive, $-1$ if the argument is negative, and $0$ if the argument is exactly $0.$ — Will Jagy, Nov 14 '13 at 06:01

score 4 · Accepted Answer · answered Nov 14 '13 at 06:04

4

The value $\operatorname{sign}(x)$ equals $-1$, $0$, or $1$ depending upon whether the value $x$ is negative, zero, or positive. Sometimes this is written as $\operatorname{sgn}(x)$ as is the case here.

answered Nov 14 '13 at 06:04

J. W. Perry

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Thank you for the explanation. – Matt Nov 14 '13 at 06:14

What does 'sign' mean in an equation?

1 Answers1