together on the sheet. As long as we
recognize a blank as a graph, the scribing
of a single graph is a case of scribing two graphs
together, of which a blank is one. The second
sign is the scroll. These two are the only indispensible
signs; but we recognize as a third
sign the filling up of an area with a So much of the system of existential graphs
as I have thus far described I call the alpha
part of the system.
There are certain ways in which graphs
scribed on the sheet of assertion can be
modified without any possibility of changing
a true graph into a false one. Such modifications,
I call permissible transformations.
In particular those which can be proved
by the principles of the alpha part of the system to be
permissible, that is, never to be capable of
changing a true graph into a false one
are called alpha permissible transformations.
The alpha part of the system establishes
three signs besides the graphs themselves.
The first sign consists in scribing two graphs
EN