Sebastian Hungerecker wrote:
> Am Freitag 04 September 2009 11:25:04 schrieb Ralf Mueller:
>   
>> sure, but [[]] has a subarray. so, shouldn't [[]].transpose have one too?
>>     
>
> Well, [[1],[2]] has two subarrays so should [[1],[2]].transpose have two 
> subarrays too?
> As I said, the number of subarrays in the result equals the number of items 
> per subarray in the source. I find this completely consistent.
>
>   
>> To point it out in a more general way: I thought, if 'transpose' can be
>> applied to an array, it should behave like an involution:
>> a.transpose.transpose = a.
>>     
>
> If both [[]].transpose and [[],[]].transpose would return [[]], that still 
> wouldn't be true (because then [[],[]].transpose.transpose would be [[]]).
>   
Yes, I was contradictory to myself ;(
And a.transpose.transpose = a is true for 'non-degenerated' a.
Have to program a bit more careful (not too much guessing).

thanks again
ralf