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science of the logical possibility and impossibility
of hypotheses. Upon that definition first
put forth by my father Benjamin Peirce
in 1870, mathematicians are now
pretty unanimously agreed. Pure
mathematics differs from mathematics
in general in not admitting into its
hypotheses any element that does affect
their logical possibility or impossibility.
Thus, the pure mathematics of graphs, as
you see in those pages of the syllabus, says
nothing at all about the logical interpretation
of graphs but defines them exclusively
by their logical relations to one another.
So the pure mathematical presentation of