Here the expansion was used.
Calculating
Definition:
- ,
- (for ),
- ,
- ,
- ,
Now:
where:
- ,
- ,
- ,
- , ()
The more compact expression is:
where
The Hausdorff recursion formula:
.
Source: T1265 = M. Lutzky “Parameter Differentiation of Exponential Operators and the Baker-Campbell-Hausdorff Formula”; Journal of Mathematics Physics, Vol 9, N 7, July 1968.