The public domain is the wrong place for this, but you can certainly grant irrevocable patent licenses. IIRC this is how the GPL3 works. (Not that you'd have to

The public domain is the wrong place for this, but you can certainly grant irrevocable patent licenses. IIRC this is how the GPL3 works. (Not that you'd have to license under the GPL to use the same strategy, it just shows it's possible)