Query optimisation in distributed database systems addresses the challenge of selecting an efficient execution plan across multiple networked nodes. Owing to the combinatorial explosion of possible ...

$$\begin{aligned} \begin{aligned} X'= \left\{ \begin{array}{l} x_1 S_3 S_5\ldots l_{n-3} S_{n-1 }+x_3 S_5\ldots S_{n-3 }S_{n-1}+\cdots +x_{n-3 } S_{n-1 }+x_{n-1 ...