priority of the Linux group & user

Question

My current user & group is baohua-baohua.If I create a file belonging to baohua-test, the priority of the user is higher than that of the group (if the user's permission is rw-, the file is rw).If I create a file belonging to test-baohua, the priority of the group is higher than that of the user (if the group's permission is rw-, the file is rw). for example:

Why is that

Answer 1

Assumption: no ACL.

• Are you the user that owns the file?
  • Yes → The owner's permissions matter. Nothing else matters. End procedure.
    ^{(The file belonging to baohua:test fits this case.)}
  • No → Are you in the group that owns the file?
    • Yes → The group's permissions matter. Nothing else matters. End procedure.
      ^{(The file belonging to test:baohua fits this case.)}
    • No → The other's permissions matter. End procedure.