Thank you Shreddy. It was exactly information I was looking for. I quote the autor of one of the posts.
'It's best if INITIAL=NEXT and PCT_INCREASE=0 for the tablespace. Drop and recreate if necessary. This relates to the limited duration of temporary objects. Once their usefulness is ended, temporary objects are dropped and the extents allocated to them are returned to the tablespace for later use by other sorts or temporary operations. They are not deallocated. The next time any operation goes looking for space it will find an extent ready and waiting.'
Please someone explain this sentence to me:'They are not deallocated.'
Thank you.