Oh. I took that to mean {ta za'e gumri sa bergu} means {ta za'e bergu} but {ta za'e gumri sa ba'e bergu} means {ta ba'e bergu}. But in terms of erasure, presumably BAhE and the marked word are distinct for {si} as well, and for {su} of course it doesn't matter. So the definition should read "The two words are considered distinct for "si"/"sa" matching purposes."