Help for understanding a mathematical expression

djamel said:
I need help to figure out the notation below:
View attachment 25942
Click to expand...
We need some context. Please show where this came from, and locate where they have defined the variables (and quite likely the notation). At least, tell us what this is about, and what the parts you do understand mean. Which parts do you not understand?
 
Dr.Peterson said:
We need some context. Please show where this came from, and locate where they have defined the variables (and quite likely the notation). At least, tell us what this is about, and what the parts you do understand mean. Which parts do you not understand?
Click to expand...
P(u) is a set of nodes.
L(v) is a set of nodes.
I want to understand how to calculate this kind of summation.
 
Subhotosh Khan said:
Which SUBJECT assigned this problem?

What is the name of your textbook or reference book?
Click to expand...
Ref: A. Dehghan, and A. H. Banihashemi, “Counting Short Cycles in Bipartite Graphs: A Fast Technique/Algorithm and a Hardness Result,” IEEE Transactions on Communications, vol. 68, pp. 1378-1390, Mar. 2020.
 
djamel said:
P(u) is a set of nodes.
L(v) is a set of nodes.
I want to understand how to calculate this kind of summation.
Click to expand...
So I suppose the part you are asking about is the notation [MATH]\sum_{a\in A} f(a)[/MATH]. What this means is that you are summing over all elements of set A. In principle, you would just list all the nodes in that set, and evaluate the summand for each of them.

This is one of the uses explained here.

Possibly we could say more if you sent us an image of the expression in context.
 
First, I would like to thank Dr.Peterson and Subhotosh Khan for their replay and their time. Second, the problem that I had is I couldn't understand the notation that follows ∑, and after I checked out the link above, given by Dr.Peterson, I find that this notation is the binomial coefficients that is given by the formula:
1616594155248.png
 
Last edited:
djamel said:
First, I would like to thank Dr.Peterson and Subhotosh Khan for their replay and their time. Second, the problem that I had is I couldn't understand the notation that follows ∑, and after I checked out the link above, given by Dr.Peterson, I find that this notation is the binomial coefficients that is given by the formula:
View attachment 25958
Click to expand...
Yes, and we could have helped you much quicker if you had stated specifically that it was the parentheses that you didn't understand.

My general advice in asking for help is to say far more than you think is needed, because what is obviously the obscure part to you may be the last thing someone else would think you need help with! The next thing I was thinking of explaining, after the "summation" you explicitly asked about, was the absolute value.
 
You must log in or register to reply here.
Top