ddb174 wrote:That doesn't matter; trademarks don't have to be registered. Being registered affects the law regarding them, but not in a way that really helps here.
The KDE E.V. does not appear to claim trademark on Plasma. There's no indication on any of their plasma pages of such a claim. Even if they did, the text describing libHSPlasma makes it clear it has nothing to do with desktop environments. Additionally, it's clear on both this forum and the google page that the author has nothing to do with the KDE E.V. or any of its projects. Chance of confusion is near zero.
Cyan Worlds may or may not lay claim to Plasma as a trademark for their engine. Since there's no public website, we can't really know. Since the engine isn't really marketed openly there is little chance from confusion, and as above it's fairly clear there is no direct association with the company (in this case, Cyan Worlds). The chance of confusion is higher here, and may become even higher once Cyan finally released the Plasma source code. However, If Cyan releases the code as "Plasma" and then enforces a trademark, that would severely restrict the open source idea.
On top of that, This project has been around for over a year now. Cyan certainly knows it exists, and in that time they've both created a Plasma-based game for a 3rd party and re-launched their own Plasma-based project. Obviously they could, in the future, change their minds on allowing use of the Plasma name, but this whole community is based around "Hope Cyan doesn't change their minds", so trying to say that's a problem for this particular project seems silly to me. Yes, they shut down h'uru, but a lot has changed since then regarding Cyan's attitude towards fan involvement.