SELECT TIMESTAMP WITH TIME ZONE ... AT TIME ZOME as inverted meaning with UTC times...

Hi,

From the documentation:

# SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME ZONE 'MST';
      timezone
---------------------
 2001-02-16 18:38:40

MST is UTC-07, so i would expect that i can replace MST with UTC-07, but:

# SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME
ZONE 'UTC-07';
      timezone
---------------------
 2001-02-17 08:38:40

The time returned is at UTC+07....

Lets try at UTC+07 instead:

# SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME
ZONE 'UTC+07';
      timezone
---------------------
 2001-02-16 18:38:40

I this a bug or a feature, and if it is a feature, whats the rational behind it?

Regards
Andreas