A shorter proof of Lemma A.6 (arXiv:1005.0768)
  For the convenience of readers of the article {\em No-arbitrage pricing under systemic risk: accounting for cross-ownership} (Fischer, 2012, arXiv:1005.0768), a full proof of Lemma A.5 and a shorter proof of Lemma A.6 of that paper are provided. 
Tom Fischer
q-fin.PR