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is permissible within a single cut.

Thus if
If x is transformable into y
...
and so on indefinitely. In short, whatever
transformation is permissible on the sheet of
assertion is permissible within any even
number of cuts while the reverse transformation
is permissible within any odd number of
cuts. For example, since any graph can
be erased on the sheet of assertion any graph
can be erased within any even number
of cuts while any graph can be inserted