{[], se_lt_x :: [a-A, c-C] =*= se_lt_y :: [d-A, f-F] =*= se_lt_z :: [i-F, g-G]}
The shared variable A joins se_lt_x and se_lt_y; the shared variable F joins se_lt_y and se_lt_z
se_lt_x
se_lt_y
se_lt_z