Thank you for this hint.
As I don't understand 
the expression
$regexp($reverse($regexp($regexp($reverse($regexp($regexp(%Genre%,'^(\s+;*|\s*;+)+|(\s+;*|\s*;+)+$|((?<=;)\s+)|(\s+(?=;))',),'^|,';')),'(;[^;]+)(?=(\1|;.*?\1))',),'^;+|;+,)),'(?<=;)',' ')
in detail, I am not shure how to deal with this.
--.--
Another idea is to find the beginning of the redundant second part of the string and split COPYRIGHT in 2 values and delete the second one. But stil have to build an expression that scans the string ....