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Unformatted text preview: our proof requires several similar subproofs,
each containing a similar sequence of steps.
To cut or copy a range of steps, you must ﬁrst select the steps.
Shift-clicking on a step will select the range of steps between the
focus step and that step. You cannot select a range containing just
one step, so shift-clicking on the focus step will do nothing.
A grey will appear, showing which steps are selected. If the
rectangle doesn’t contain the steps you want, click somewhere else
in the proof and the rectangle will disappear. You can then try
selecting the steps again. Note, however, that Fitch will not allow
the selection rectangle to cut a subproof in half: you must either
select steps entirely from within a subproof, or else select the subproof as a whole. When the rectangle contains exactly the steps
you want, choose Cut or Copy from the Edit menu. Both of
these commands place a copy of the steps on the clipboard; Cut
also deletes the selected steps from the proof.
Once a sequence of steps is on the clipboard, choosing Paste
will insert the steps at the point of focus. If you are currently
focused on an empty step, the pasted steps will replace the empty Using Fitch / 43 step. If you are currently focused on a step that is not empty, the
pasted steps will be inserted after the focused step.
If you want to paste steps into your proof immediately following
a subproof, but not as part of the subproof, you will have to end
the subproof before pasting. This will give you an empty step
outside the subproof and Paste will replace this empty step with
the steps on the clipboard.
When you paste steps into a proof, Fitch will try to keep track
of the appropriate supports for those steps. Sometimes, though,
the supports for the pasted steps will no longer be “legal” in the
new location, for example if you paste a step into the proof at a
point earlier than one of its support steps. In such cases, Fitch will
remove the illegal support from the step’s list of supports.
Note that this method also gives you a handy way to delete a
large number of steps. Rather than repeatedly choosing Delete
Step from the Proof menu, simply select all of the steps you wish
to delete, and choose Clear from the Edit menu. Simply hitting
the Delete key will also delete the selected range of steps. 4.5 Printing proofs To print a proof, choose Print. . . from the File menu. When
you do this, you will be given the standard print dialog box. Once
you have chosen any printer options you want to use, click on the
Print button in the dialog box. In the printed proof Fitch adds
numbers to all of the steps and uses these numbers to indicate each
step’s supports so that the printed proofs look like the proofs in
the textbook. 4.6 Setting up exercises Fitch has two modes of operation, user mode and author mode.
Students normally use the program in user mode, so exercise ﬁles
are always opened in user mode. This mode allows you to construct
proofs, but not to change the premises or go...
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This document was uploaded on 01/26/2014.
- Winter '14