They could just rename it, and it would still remain Amiga, since OS4 has been written using the original 3.1 sources.
So you can just ignore the fact that it's based on Amiga IP? I'm afraid that will not fly.
Hmm, true, Hyperion can own OS4 only in case of Amiga Inc. bankruptcy, if I recall correctly.
On a lighter note: It's quite hilarious that some have been happy to shoot down MorphOS for just rumours of being based on some 3.1 source code (which it is not, obviosly. Some belgian guy appears to have some serious obsession). When it appears OS4 could really be using the IP illegally... it's completely different story, in fact it will be announced as a positive fact. Talk about double standards.
Only if it was legal, and at first I thought it could be, but now I remembered what's inside Hyperion's contract. On a related note, YellowTab has done an IP theft with Zeta, and they have been lucky Palm hasn't sued them while Zeta was still available commercially.