Using the EG Applet

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Using the EG Applet

• Bram van Heuveln

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Contents

• General Comments
• Some general comments regarding the use of the
  applet
• Work Area
• Instructions for creating and editing graphs
• Proof Area
• Instructions for manipulating graphs in
  accordance with the inference rules

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General CommentsProof Area and Work Area

• The applet consists of 2 windows
• Work Area This is the area in which the user can
  create and edit graphs
• Proof Area This is the area in which the user
  can manipulate graphs using the EG inference rules

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General CommentsCanvas, Buttons, and Menu

• Each window has 2 parts
• Canvas This is the big white area. This is where
  the graphs will be drawn.
• A Menu and Button Bar A bar with menus and
  buttons containing operations that can be
  performed on the graphs on the canvas.

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General CommentsSelecting an object

• When operating on a graph, the user frequently
  has to select part of the graph.
• To select a proposition, click on the proposition
• To select a cut, click at any place that is
  inside the cut but outside of any other objects
  within that cut.
• The selected object will become high-lighted.
• The user frequently has to hold the mouse button
  after selecting the object, and perform the
  operation before releasing the mouse button

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General CommentsOverlap

• None of the parts of a graph may overlap, as this
  will form an ungrammatical expression. So, the
  applet is set up such that
• When the user tries to create a new object that
  overlaps with an already existing one, then the
  new object will not be inserted.
• When the user tries to drag an object over
  another, the dragged object will be put back at
  its original location.

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General CommentsMaking Room

• Because overlap is not allowed, the user must
  always make sure that there is room for objects
  to be inserted, whether those objects are new or
  whether they are being dragged or copied from
  elsewhere.

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General CommentsOperations

• When the user wants to perform an operation, the
  user has to select that operation from either the
  Menu Bar or the Button Bar (Buttons go fastest!).
• However, before performing any kind of operation,
  the user has to make sure that there is room for
  the operation to take place
• From now on, it is assumed that the user has made
  the appropriate choice of operation, and has made
  room for it to take place.

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Work AreaWork Area Creating and Editing Graphs

• The Work Area is for creating and editing graphs.
• Work Area contains the following operations
• Inserting new propositions or cuts
• Moving propositions or cuts
• Resizing cuts
• Copying propositions or cuts
• Deleting propositions or cuts

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Work AreaInsert Proposition

• To insert a simple proposition (e.g. P)
• 1. Click at the location where you want the
  proposition to be inserted
• 2. Type the letter you want to have inserted
• Note
• Simple propositions must be a single letter
• A lower-case a is seen as a different
  proposition than a higher-case A!

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Work AreaInsert Cut

• To insert a cut
• 1. Click at the desired location of one of the
  corners of the cut to be inserted
• 2. While holding the mouse button, move to the
  opposite corner (high-lighted cut should appear
  and move along)
• Note
• It doesnt matter which corner you start with

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Work AreaDrag 1

• To drag or move a single cut or simple
  proposition elsewhere
• 1. Select the object to be moved
• 2. While holding the mouse button, move the
  selected object to desired location

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Work AreaDrag

• To drag a cut together with all its contents
• Like Drag 1
• Note
• Simple propositions can be moved with Drag as
  well.
• To drag all objects on the canvas, select any
  place on the canvas outside all objects.

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Work AreaResize 1

• To resize a single cut
• 1. Select the cut to be resized, but make sure to
  click in the quadrant corresponding to the corner
  that will be moved (e.g. if you want to move the
  top-right corner, click somewhere in the
  top-right quadrant)
• 2. While holding the mouse button, move corner to
  desired location

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Work AreaResize

• To resize a cut together with all its contents
• Resize 1
• Note
• This operation does not work properly as of this
  point use with care!

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Work AreaCopy 1

• To copy a simple proposition or single cut
• 1. Select the object to be copied
• 2. While holding the mouse button, move copy to
  desired location

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Work AreaCopy

• To copy a cut together with all its contents
• Like Copy 1
• Note
• To make a copy of all objects on the canvas,
  select any place on the canvas outside all
  objects.

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Work AreaDelete 1

• To delete a simple proposition or single cut
• 1. Select object to be deleted
• Note
• To avoid the unintended deletion of the wrong
  object, hold the mouse button before releasing it
  to see the selected object. If this is not the
  right object, move the mouse to change the
  selected object to the correct object.

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Work AreaDelete

• To delete a cut together with all its contents
• Like delete 1
• Note
• Again, the user can hold the mouse button while
  moving the mouse to make sure the right object
  gets deleted.
• To delete all objects on the canvas, select any
  place on the canvas outside of all objects.

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Work AreaMove to Proof Area

• To move graphs to be Proof Area
• 1. Open the Proof Area window.
• 2. Select the graphs from the Work Area you want
  to move to the Proof Area (to select all, click
  anywhere on the Work Area canvas outside all
  objects).
• 3. Click anywhere on the canvas of the Proof Area
• 4. While holding mouse button, move copy to
  desired location.

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Proof AreaProof Area Manipulating Graphs

• The Proof Area is for manipulating Graphs
  according to the EG inference rules.
• The Proof Area contains the following inference
  rule operations
• Insert/Erase Double Cut
• Insertion and Erasure
• Iteration and Deiteration

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Proof AreaIllegal uses of Inference Rules

• The applet checks to see if the user applies the
  inference rules correctly.
• When the user makes an illegal use of an
  inference rule (e.g. the user tries to erase an
  object from an odd level), then the intended
  manipulation will not take place.

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Proof AreaEditing

• In the Proof Area, the user can still edit
  (resize and drag) graphs, as long as the logical
  structure of the graph does not change.
• If the logical structure does change, then the
  operation will not be performed.
• Resizing and dragging serves 2 purposes
• to obtain a fresh perspective on a graph
• to make room for other operations

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Proof AreaInsert Double Cut

• To insert a double cut around any subgraph
• Like Insert Cut
• Note
• When drawing the double cut, only a single cut
  will be shown. The second cut will be drawn
  inside this cut when the mouse button is released
  (be sure to leave some room).

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Proof AreaErase Double Cut

• To erase a double cut
• Click anywhere between the two cuts that make up
  the double cut.
• Note
• The user can hold the mouse button and move the
  mouse to make sure the right double cut gets
  selected.

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Proof AreaInsertion

• To insert any graph on an odd level
• 1. Create the graph to be inserted in the Work
  Area before selecting Insertion
• 2. Select the graph on the Work Area that needs
  to be inserted.
• 3. Click anywhere on the Proof Area (a copy will
  appear)
• 4. While holding the mouse button, move the copy
  to the desired location

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Proof AreaErasure

• To erase any subgraph from an even level
• Select the subgraph to be erased
• Note
• Hold the mouse button and move the mouse to make
  sure the right subgraph gets erased.

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Proof AreaIteration

• To iterate any subgraph on the same or any nested
  level
• Like Copy

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Proof AreaDeiteration

• To deiterate a subgraph
• Select the graph to be deiterated
• Note
• The applet will check if the selected subgraph is
  a copy of another subgraph existing at the same
  or any nested level.
• Hold the mouse button and move the mouse to make
  sure the right subgraph gets deiterated.