3

2

is that I want some means of determining with
certainty whether a graph is possible or not. Oh,
but that answer won't do. The means I seek is a
means by method of transformation of graphs. What, then,
does the word possible mean, when translated into terms of
transformation of graphs? The answer is
that a graph is alpha-possible if the alpha rules
of graph-transformation can being performed on a
sheet on which this graph is scribed can never
result in the cancelling of the entire sheet. Very
well; then what is wanted is a method by which
to ascertain whether, to begin with, the alpha
rules of graph-transformation could ever
lead to the cancelling of the entire sheet on
which the graph in question is scribed. But I