ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Sat, 07 Sep 2013 18:42:49 +0200How to use Sage (or other software) to simplify this algebraic expression ?https://ask.sagemath.org/question/10522/how-to-use-sage-or-other-software-to-simplify-this-algebraic-expression/Background: I was trying to understand the IBM 1 machine translation models when I came across a summation involving summation over Kronecker Delta, which was later simplified. I want to know if it is possible to automagically simplify complicated summations in Sage (I haven't ever used symbolic math toolbozes before)
All images are screenshots of [some slides of NLP course at jhu](http://www.cs.jhu.edu/~jason/465/PowerPoint/lect32a-mt-word-based-models.pdf)
Detailed Question: Is it possible to use Sage to simplify equations such as the following ![Expression to simplify](http://imageshack.us/a/img856/8147/ly3v.png)
and the definitions of the terms are $\delta$ is the Kronecker delta and $p(a | e,f)$ is defined as
![image description](http://imageshack.us/a/img812/4281/xbih.png)
where a and t are defined as
![image description](http://imageshack.us/a/img856/1227/ypfu.png)
The final simplified form of the equation is ![image description](http://imageshack.us/a/img19/7818/x5sq.png)
Sat, 07 Sep 2013 18:42:49 +0200https://ask.sagemath.org/question/10522/how-to-use-sage-or-other-software-to-simplify-this-algebraic-expression/