# What exactly does up triangle \land symbol mean in the context of peak detection?

Folks, I'm reading this paper: User Adaptive QRS Detection Based on One Target Clustering and Correlation Coefficient, and have a question about notation.

In describing peak-detection, they use the following notation: I understand this to mean something like for j=0 to 2: S(i-j) should be greater than S(i-j-1), and S(i+j+1) should be greater than S(i+J), where S is the signal.

But what is that up arrow symbol called? Is it just a logical and? As in this must be true for each of the j?

Thanks!

• hm, I'm starting to follow the references given in the paragraph just above these two equations: What about  from the same authors? – Marcus Müller May 7 at 11:41
• I checked with the author and yes, it just means conjunction: logical and. So just as \sum_{j=0}^2{x_j} means x_0 + x_1 + x_2, \land_{j=0}^2{x_j} means x_0 \land x_1 \land x_2 – Jabavu Adams May 7 at 15:59
• that would make a great answer! It's totally OK to answer your own questions. – Marcus Müller May 7 at 16:01