【答案】应助回帖

2楼: Originally posted by hank612 at 2014-04-23 23:23:07
楼主误会了。 证明中只用到了

\\mathbb {\Sum_{i.j}\Sum_{p,q} A_{ij}S_{jq}B_{qp}S_{ip} \cdot u_{ip}^2
= \Sum_{i.j}\Sum_{p,q} A_{ij}S_{jq}B_{qp}S_{ip} \cdot u_{jq}^2
}  

而这个双重求和， 由于指标 ...

3楼: Originally posted by hank612 at 2014-04-23 23:28:07
\mathbb{ \sum_{i,j}\sum_{p,q} A_{ij}S_{jq}B_{qp}S_{ip} \cdot u_{ip}^2}


我再试试latex排版，希望楼主能看清楚...