Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

I have a simple question, but it is hard to google it. I have this equation here:

$$y(t, x) = \sum_{i=1}^{d}(|x_i| \wedge t)^{2} $$

Here $x$ is a size $d$ signal and $t$ is just a scalar. I am not sure how to read that equation in english... I understand everything except for how they use the $\wedge$ here...

If context helps, this is part of a cost function, based on a threshold $t$ that is selected, for your vector $x$.

share|improve this question
    
It probably means the minimum of $|x_i|$ and $t$. –  user1551 Jan 25 '13 at 3:12
    
@user1551 Are you sure about that? If it helps, "t" is supposed to signify a threshold value, and $x(i)$ is just some sample from a d-length vector. –  Mohammad Jan 25 '13 at 3:15
    
@AlanSimonin Please see the context. There is no cross-product here. –  Mohammad Jan 25 '13 at 3:26
    
Of course I am not sure, because I don't see why one would want to take the minimum of a spatial quantity ($|x_i|$) and a temporal quantity ($t$). Yet the wedge symbol usually has three meanings: logical conjunction, some sort of "wedge product" and the minimum function. As both $|x_i|$ and $t$ are scalars, we can rule out the first two possibilities. So the minimum function is the most plausible explanation I can think of. –  user1551 Jan 25 '13 at 3:28
1  
Yes, I mean $(|x_i|\wedge t)\equiv\min(|x_i|,t)$. –  user1551 Jan 25 '13 at 3:32
show 4 more comments

1 Answer

up vote 2 down vote accepted

$|x_i|\wedge t$ probably means $\min(|x_i|,t)$.

There are three usual meanings of the wedge ($\wedge$) symbol: logical conjunction, some sort of "wedge product" and the minimum function. As both $|x_i|$ and $t$ are scalars, we can rule out the first two possibilities. So the minimum function is the most plausible interpretation I can think of. But certainly, you should look at the context of your equation to make sure that this is a correct interpretation.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.