It's a gray area and currently being litigated. If Oracle prevails, then NVidia absolutely would be in a position to shut down compatible implementations of CUD

It's a gray area and currently being litigated. If Oracle prevails, then NVidia absolutely would be in a position to shut down compatible implementations of CUDA, or dictate the terms under which they might or might not be able to continue to exist. Using open standards avoids this risk, though some companies are unwilling to work with Khronos, citing (not publicly detailed) legal concerns. [1]: https://en.wikipedia.org/wiki/Google_v._Oracle_America https://en.wikipedia.org/wiki/Google_v._Oracle_America