2020/06/17 by Mencattini, Igor, Quesney, Alexandre
#16T05 #16T10 #16T30 #17A30 #17A50 #17B35 #17D99 #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2006.10127
In the first part of this letter it will be shown that the post-Lie Magnus expansion can be interpreted as a crossed morphism between two (local) Lie group. The second part will be devoted to present two combinatorial methods, both based on special tubings on planar trees, to compute the coefficients of this remarkable formal series.