43

42

which are not graphs are the writing scribing putting of two
graph-replicas upon the same area, which
if we remember that a blank is a graph, is seen
to include the scribing of a single graph as
a special case. This idea that scribing
a graph is a transformation of a graph
already accepted is a very useful one.
The other sign is the scroll.

I have just defined a permissible
transformation as one which conforms
to a general type which in no case can
transform a true graph into a false
one. But what do we mean by a true
graph and a false one? I will not stop
at present to analyze fully the meaning,