Gauge invariance of the technifermion condensate in walking technicolor

In this article we present an analysis of the gauge invariance of the technifermion condensate and critical coupling determined from the gap equation to O(α2) in the static limit of walking technicolor. This is an extension of a previous work in which the proof of gauge invariance was restricted to ξ=0 and ξ=-3 gauges. We also briefly discuss how to generalize the proof to O(α3) and higher where β(α) cannot be set equal to zero for arbitrary values of α