User blog comment:Ynought/Array hierarchy/@comment-37829460-20190315202554/@comment-36957202-20190417120520

v is a variable what else would it be

it think you meant N and that is the set of all positive integers

i and j are variables where i isn't k or the number of variables in the array and j is less than i

What is the weird e do you mean @ and thats just a symbol which represents the value of all variables in the array added together

and N_>0 is the set of all integers bigger than 0