Deutsche Bahn offers a "BahnCard" which offers the holder a 25, 50, or 100% discount on Deutsche Bahn rail tickets.
The wiki page mentions that, due to the "TEE Rail Alliance", the DB BahnCard 25 and BahnCard 50 can be used to get a discount on a trip in Switzerland that begins in Germany.
Is the BahnCard 25/50 also valid for a discount on a journey on Swiss trains that takes place entirely within Switzerland?