GREENLAND is not part of the Schengen area.
A visa to enter DENMARK or another Schengen country is not valid for entry into GREENLAND.
A visa for DENMARK does not give the holder the right to enter GREENLAND unless it is stated on the visa, just as a visa for GREENLAND does not give the holder the right to enter DENMARK, if it is not stated on the visa. Visa is required for entering GREENLAND regardless of the person having a residence permit in DENMARK. Correspondingly, a visa is required when entering DENMARK, even though the person has a residence permit in GREENLAND.