Can Mahayana Monks ordain Theravadins?

I wonder if Mahayanabhikkhus can perform a Theravadin ordination and have the ordination be recognized as valid by the Theravadin bhikkhusangha without doing dalhikamma? What if the theravadins do a dalhikamma for a monk who took theravadin ordination performed by mahayana monks? Can he get full acceptance in the Theravada then? If not, can a dalhikamma be performed for the Mahayana monks as to make them eligible to perform Theravadin ordinations or must they re-ordain as Theravadins? Finally, can a monk be considered to have full ordination in both mahayana and theravada?