ENPages
267
21
But all this will be made infinitely clearer by studying how a graph once written may be altered without danger of rendering its asserting false. There are four Basic Rights of Transfornation. Right I. Any evenly enclosed graph may be erased; and under odd enclosures, already written, any graph can be inserted.
Right II. Any graph precisely like another that is written under no other enclosures than its own, and connected with the same graphs, can be erased. Any graph can be repeated under the same or any already written additional enclosures, with the same connections.
268
22
Right III. Two encolsures one within the other with nothing between can anywhere be erased or inserted.
Right IV. Under an enclosure containing a pseudograph,it makes no difference what else is written, and the enclosure with all it encloss may be erased.
By using these rights we can draw from any premisses any inferences that they justify and not merely the stupid syllogiams of the logic-books. I will now proceed to prove to you that we have these rights, and you will thereby gain a new light on the interpretation of graphs. The proof is excessively simple; but of course it is necessary to pay attention in order to follow it.
Of course, we have at any moment a right to clean everything on the the blackboaard by a general erasure; for that is merely to cease insisting on our
