Cimber Air just started flying Copenhagen-Norrkoping, using CRJ 200. Skyways also flies that route, using Fokker 50.
Since both Skyways and Cimber Air are EB partners, this causes a little bit of a tricky situation.
Right now all booking systems (including SAS) will give you Skyways flights for codeshares to NRK, but the question is if the Cimber Air flights will be added to the system soon?
The EB pages states that you can earn and burn EB miles on Cimber Air, but it seems to be no easy way to book trips connecting through CPH to NRK on Cimber.
Would SAS assign codeshare flight numbers to both Skyways and Cimber Air flights or will they continue with just the Skyways flights?
Most people would choose a CRJ 200 over a F50 any day, so I see no reason why Cimber Air couldn't be successful. A lot of people avoid the Skyways flights since they are propeller flights. Jet flights are predicted to much more likely to be used. Just look at the traffic data comparing the Skyways flights to the SAS flights a couple of years ago.

Skyways isn't exactly making a profit on the CPH-NRK route so they are likely to cancel it if the competition from Cimber Air is too strong, so perhaps SAS will have no choice but to use Cimber Air as the partner airline to NRK.

Possible side effect:

The Skyways CPH-NRK flight continues on to Orebro so if Skyways cancels CPH-NRK, ORB will most likely lose their CPH service. Skyways tried a direct CPH-ORB route but couldn't make a profit. Considering that Orebro airport is likely to lose a lot of its government support (people are close to Stockholm and can get to Arlanda in less than two hours), I can't see how Skyways would keep a CPH-ORB route open if the ORB airport is forced to raise its landing and service fees because of the decrease in government grants.