... numerator and denominator reproduce Eq. (2.7) with c → c − 1 andthe parameters αb+c, βa+cremoved. This concludes the recurrence.Note immediately the symmetry between the sets of variables ... 1. They are made of three sets of a, b, c nested arches. Herea, b, c are arbitrary integers such that a + b + c = n where the size of the system is2n. The model depends on 2n complex numbers ... a consequence we see that we can divide our regioninto pieces separated by holes, so that these pieces have no influence on each other,and the summation over plane partitions factorizes accordingly....