Abstract This paper is concerned with the optimal number of redundant allocation to n -component coherent systems consisting heterogeneous dependent components. We assume that system built up L groups different components, $L\geq 1$ , where there are $n_i$ components in group i and $\sum_{i=1}^{L}n_i=n$ . The problem interest allocate $v_i$ active each component type $i=1,\dots, L$ To get value...