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Unformatted text preview: he size and shape of
the block that is created when the New Block button is pressed.
You have the option of being presented with a dialog box, always
creating the same kind of block, or allowing Tarski’s World to
choose a size and shape for you.
The ﬁnal option speciﬁc to Tarski’s World concerns the display
of text in the sentence pane. You may opt to specify a default font
size for the sentence panel.
There is a global preference which controls whether all of the
applications check for updates when they are launched. If this box
is checked, the application will determine if an update is available,
and ask if you want to download and install it. Chapter 4 Using Fitch
Fitch is an application that makes it easy to construct formal proofs
in ﬁrst-order logic. We begin with instructions on how to start and
stop Fitch, and explain the basic layout of the screen. 4.1 Getting started The Fitch application is contained inside the folder called Fitch
Folder. Also in this folder is a folder called Fitch Exercise Files, in
which you will ﬁnd the Fitch exercise ﬁles referred to in the book.
When Fitch is running, you will see (from top to bottom) the
ubiquitous menu bar, a narrow tool bar, a wider, gray sentence
tool bar, and a large, mostly blank window, called the “proof window,” with a “goal strip” at the bottom.Here are the basic facts
to remember about each of these. 4.1.1 The menus Fitch has the following menus:
◦ File: This menu lets you start new proof ﬁles, open existing
proofs, save proofs, and print proofs.
◦ Edit: This is the customary edit menu allowing one to cut,
copy and paste items in proofs.
30 Using Fitch / 31 Figure 4.1: Main Fitch window. 32 / LPL Software Manual ◦ Proof: The items on this menu allow you to add steps to
proofs, to begin and end subproofs, to check the correctness
of proofs, and to display step numbers.
◦ Goal: The items on this menu allow your instructor to set
goals in problems and allow you to see whether any special
constraints apply to the goals.
◦ Window: This menu gives you access to various Fitch ﬁles
you have open, and allows you to change the font and appearance of your open windows.
◦ Help: This menu allows you to get help on using the application, and also to check whether updates are available. 4.1.2 The proof tool bar The narrow tool bar at the top of the window is called the “proof
tool bar.” This is like the window tool bar in Tarski’s World,
and contains buttons which allow you to control the display of the
proof. These tools include buttons for changing the font to bold
or italic, and to control the size of text in the proof. There are
also buttons for checking the current step, and the whole proof.
Finally, there are buttons to print the proof, and to open the help
system for the application. 4.1.3 The sentence tool bar The strip containing logical symbols and predicates located at the
top of the proof window is called the “sentence tool bar.” It is like
the sentence tool bar in Tarski’s World, and is used for writing and
editing in the p...
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This document was uploaded on 01/26/2014.
- Winter '14