File Access - Does Owner Access Override Group Access?

[Charlie Dennett]

I was experimenting with file access permissions and came across the 
following.  

I created a text file in my home directory.  It had read and write access
for the owner (that's me) and read only access at both the group and world 
level.  I then did a chmod on the file and gave it 077 as the access mask.
This gave it full access to both group and world but took away all access
at the owner level.  I did an ls -gl and a groups command and the file did
belong to the group of which I was a member.  However, when I tried to cat
the file, the system returned the message 'Permission denied'.  

Does this mean that owner level access overrides group and/or world access?

Even stranger - I next tried to remove the file with the rm command and
it worked!  

I tried looking in the manuals for something to explain about access modes
but have so far been unsuccessful.  Perhaps someone out there could explain
what is going on.  

The system I am using is a SUN 3/260 running version 4.2 release 3.5.  I do
not know if this is unique to SUN or not.
-- 
Charlie Dennett - Eastman Kodak Company
UUCP: ...rutgers!rochester!kodak!dennett 
      ...rutgers!rochester!kodak!cygnus!dennett