begin
definition
let IT be ( ( ) ( )
G_Net ) ;
end;
definition
let IT be ( ( ) ( )
G_Net ) ;
end;
definition
let X be ( ( ) ( )
set ) ;
end;
definition
let x be ( ( ) ( )
set ) ;
end;
definition
let X,
Y be ( ( ) ( )
set ) ;
end;
definition
let N be ( ( ) ( )
G_Net ) ;
end;