Added x+1+y≡1+x+y (ER version).
Added x+1+y≡1+x+y (ER version).

Ignore-this: e099f22302e7b85516d7b432f9309d04

darcs-hash:20100531140940-3bd4e-8dfca741032e39e7dabeb662da649d5f5a74d439.gz

asr/fotc,asr/fotc