# Non integer index of summation [closed]

I have following equation:

I would like to use summation for the above equation. The index of summation is not an integer. Can I use the below equation to represent the above equation?

• That is not really a LaTeX question, but rather about math notation. May 18 at 9:37
• I’m voting to close this question because it's off-topic for TeX - LaTeX. May 18 at 22:07

The names a1.1, a1.2 etc are really unconvential for mathematical objects. Instead, consider putting the number in subscript, like $a_{1.2}$. However, if they are mathematical objects, I would consider this perfectly fine notation.
Do note however you don't want too long of a subscript under your summation! For instance, here I would put $I = \{a_{1.1}, a_{1.2}, a_{2}\}$ and then use $\sum_{i\in I}$ in the equation.
• You could even write $\sum_i$, and then say "where the sum ranges over ...". May 18 at 21:55