Indeed ! But, you need to pass properly to the limit. You can use $log_s$ (the $s$ first terms of the expansion) and then remark that, when you apply both sides to a given $f\in H$, the limit is obtained by the polynomial $log_s$. log_s$with$s$sufficiently large. 1 Indeed ! But, you need to pass properly to the limit. You can use$log_s$(the$s$first terms of the expansion) and then remark that, when you apply both sides to a given$f\in H$, the limit is obtained by the polynomial$log_s\$.