If tree is as shown below, what is the tie set for this tree?
The tie set is
\begin{array}{ll} j_3=i_1 & j_6=i_3 \\ j_4=i_2 & j_8=i_4 \\ j_1=i_2+i_4 & j_5=i_1-i_2-i_3-i_4 \\ j_2=i_1-i_3 & j_7=i_2-i_1 \end{array}