@InProceedings{Kahl-1996a,
  author       = {Wolfram Kahl},
  title        = {Algebraic Graph Derivations for Graphical Calculi},
  year         = 1997,
  series       = {LNCS},
  publisher    = {Springer-Verlag},
  volume       = 1197,
  pages        = {224--238},
  editor       = {d'Amore, Fabrizio and Paola G. Franciosa and Alberto Marchetti-Spaccamela},
  booktitle    = {Graph Theoretic Concepts in Computer Science,
		  {22nd International Workshop, WG '96, Caddenabbia,
		  Italy, June 1996, Proceedings}},
  abstract   = {Relational formalisations can be very concise and precise
and can allow short, calculational proofs under certain circumstances.
[\ldots]
In situations corresponding to the simultaneous use of many variables
in predicate logic, however,
either a style using predicate logic with point variables has to be adopted
or impractical and clumsy manipulations of tuples have to be employed
inside relation calculus.
In the application of relational formalisation
to term graphs with bound variables [\ldots]
we have been forced to employ both methods extensively,
and, independently of other approaches,
have been driven to develop a {\em graphical calculus}
for making complex relation algebraic proofs more accessible.

It turns out that,
although  our approach shares many common points
with those presented in the literature [\ldots],
it still is more general and more flexible than those approaches
since we draw heavily on additional background
in algebraic graph rewriting}
}