Normal Factor Graphs: A Diagrammatic Approach to Linear Algebra
  Inspired by some new advances on normal factor graphs (NFGs), we introduce NFGs as a simple and intuitive diagrammatic approach towards encoding some concepts from linear algebra. We illustrate with examples the workings of such an approach and settle a conjecture of Peterson on the Pfaffian. 
Ali Al-Bashabsheh, Yongyi Mao and Pascal O. Vontobel
cs.IT math.IT