Gershwin reinventions and copyright law
As far as I know, when the first performance of a copyrighted work occurred does not affect or extend the expiration date of the original copyrighted material. If that performance was recorded, then the recording's copyright would not expire until 2070, but the sheet music (or however the original score was recorded) would still become public domain sometime in the 2030s.(Also, apparently my account was deleted? I have no idea why. I took a break from this site and then it was gone. I re-regi...
