sentences:  The only possible exception to this rule would be SN 1181 whose supposed remnant, 3C 58, is home to a pulsar, but its identification using Chinese observations from 1181 is contested.The inner part of the nebula is a much smaller pulsar wind nebula that appears as a shell surrounding the pulsar.Some sources consider the Crab Nebula to be an example of both a pulsar wind nebula as well as a supernova remnant, while others separate the two phenomena based on the different sources of energy production and behaviour.