Hello, I need help in **add/sum**, there are two problems:

1. How we write triple summation (sigma) in Maple? (See pic)

I try sum(sum(sum or add(add(add but it isn't working.

2. How we write summation like in this pic?

I already try these syntax:

**for e from 1 to 9 do**

**for k from 1 to 17 do**

**if i=(2*e-1) then next else**

**constraint12[2*e-1,k]:=add(x[2*e-1,i,k],i from i in T)=1**

**end if**

**end do**

**end do**

For example, the expected result for e=2 and k=1 is like following equation:

x[2,1,1]+x[2,3,1]+x[2,4,1]+x[2,5,1]+...+x[2,17,1]+x[2,18,1]=1

But the result I get:

x[2,1,1]+**x[2,2,1]**+x[2,3,1]+...+x[2,18,1]=1

How to omit the x[2,2,1]?

Thank you.