On sub-determinants and the diameter of polyhedra

We derive a new upper bound on the diameter of a polyhedron P = {x \in Rⁿ : Ax <= b}, where A \in Z^{m\timesn}. The bound is polynomial in n and the largest absolute value of a sub-determinant of A, denoted by \Delta. More precisely, we show that the diameter of P is bounded by O(\Delta² n⁴ log n\Delta). If P is bounded, then we show that the diameter of P is at most O(\Delta² n^3.5 log n\Delta). For the special case in which A is a totally unimodular matrix, the bounds are O(n⁴ log n) and O(n^3.5 log n) respectively. This improves over the previous best bound of O(m¹⁶ n³ (log mn)³⁾ due to Dyer and Frieze.