avoid duplicate 'obtain' in veriT Isar proofs, by removing dubious condition
avoid duplicate 'obtain' in veriT Isar proofs, by removing dubious condition

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle