[Retros] What does C+ mean?

[Thomas Maeder]

Renny Bosch wrote:
 >

> Could someone please explain what the designation "C+" means?  I suspect it

> has something to do with uniqueness or minimum length but am not sure.  If

> it is explained in the Retro Corner Glossary please tell me under what

> heading.


The supposed meaning is "Correctness verified by a computer program."

But it's a good idea to always take this "information" with a grain of salt. 
 From my (Spokesman of the Sub-Committee for Computer Matters) oral report to 
the PCCC this year:

The sub-committee [...] reminds problemists not to read too much into the "C+"
tag written next to a problem; in the worst case, this tag only means that
somebody tried to use a computer to obtain some information about the
correctness of the problem.

-- 
Thomas