Decipher the mathematical expression: $\underset{l}\arg\left[\underset{l=1}{\overset{N}{\wedge}}\underset{j=1}{\overset{n}{\vee}}|m_{ij}-x_j|\right]$

Question

Can anybody explain me the meaning of the below mathematical expression in simple English? Here $\text{index}, l, i, j$ are positive integers. $m$'s and $x$'s are decimal numbers.

$$\text{index}=\underset{l}\arg\left[\underset{l=1}{\overset{N}{\wedge}}\underset{j=1}{\overset{n}{\vee}}|m_{ij}-x_j|\right]$$

Meaning of the $\wedge, \vee$ signs are not clear to me as the expression is absolutely not related to propositional logic.

I have come across the expression while studying the paper "A Low-Cost EMG-Controlled Anthropomorphic Robotic Hand for Power and Precision Grasp" (ScienceDirect link). This is equation (11) in section 2.2.1 ("Bio-signal classification subsystem").

Here's a screenshot of the surrounding text:

Answer 1

Reference [25] of your paper is H. Sossa, R. Barron and R. A. Vazquez, "Real-valued pattern classification based on extended associative memory," Proceedings of the Fifth Mexican International Conference in Computer Science, 2004. ENC 2004., Colima, Mexico, 2004, pp. 213-219.

The notation is explained towards in section 3 of that paper, just after equation (10):

In the first case, operators $\vee\equiv\max$ and $\wedge\equiv\min$ execute morphological operations on the difference of the absolute values of the elements $m_{ij}$ of $\mathbf M$ and the components $x_j$ of the pattern $\mathbf X$ to be classified. Thus $\vee_{j=1}^n |m_{lj}−x_j|$ is the metric of the max between row $l$ of $M$ and pattern $\mathbf X$, it can thus be written as $d(\mathbf x,m_l)≡\vee_{j=1}^n |m_{lj}−x_j|$, $m_l$ row of $\mathbf M$.

It's not my field, but it seems to me that anyone interested in low cost EMG should read up on EAM as expounded by Sousa, et al.