Stratified $\beta$-numbers and traveling salesman in Carnot groups

We introduce a modified version of P. Jones's $\beta$-numbers for Carnot groups which we call stratified $\beta$-numbers. We show that an analogue of Jones's traveling salesman theorem on 1-rectifiability of sets holds for any Carnot group if we replace previous notions of $\beta$-numbers in Carnot groups with stratified $\beta$-numbers. In particular, we can generalize both directions of the traveling salesman theorem giving us a characterization of subsets of Carnot groups that lie on finite length rectifiable curves. Our proof expands upon previous analysis of the Hebisch-Sikora norm for Carnot groups. In particular, we find new estimates on the drift between almost parallel line segments that take advantage of the stratified $\beta$'s and also develop a Taylor expansion technique of the norm.