keyframe T^{i+1}_j

[narutojxl]

Hello authors,
Thank you for sharing for us to learn from your excellent work.
I have a stupid question about T^{i+1}j, equ(1b) in the paper. With equ(1a) we transform all the frames in a window into the first frame of the window to get F^{i+1}{j}. If we want to calculate T^2_0, i =1, j =0, s =3. With equ(1a) , we have the following result, how to understand this result. T^{i}_{j,k} is the relative pose between T^i_j and T^i_k.