Existential Graphs Software
Dr. Russell Herman
Department of Mathematics and Statistics
University of North Carolina at Wilmington
August 2003
Overview
Test engine

Using Peirce’s Alpha Model for Existential Graphs.
Designed to test the engine

Not ready for the end user.
Ultimate Goal:

Alllogic.
men are mortal.
To make assertions using predicate
Outline of Talk
Introduce the Interface
 Simple Examples
 Future Development

Socrates is a man.
Therefore ?????
Interface – Engine Test
Expression Entry
Variable List
Parsed Expressions
Truth Table – Full or Select
Conclusions- not implemented yet
Interface – Menu Items
Built-in Examples



Modus Ponens
Modus Tollens
Conditional
Instructions

Symbols
Example 1 - Not A and B
The Steps for Entering this Expression
Type in Expression
Not = ~
 And = +
 A, B can also be full words or phrases

But cannot be one of
 Example later

Click on Add

The expression is parsed
~, +, *, ( , )
Example 1 – Not A and B
Add Expression
• Variables
• Expression
Sheet of Assertion
Truth Table
0’s - True
1’s - False
Assert
Determine when the
expressions are
true together
•A
- False
•B
- True
Example 2: Modus Ponens
Add Several
Expressions
Conditional >
A>B means
“If A then B”
Truth Table =>
Click Assert
Only True when both A
and B are True
Example 3 – Apples and Oranges
Can Use Words
Add Statements:
Apples and Oranges
and
If Apples, then Bananas
Truth Table

Conjunction of last 2
columns true?
Assert & Conclude
Apples, Oranges and
Bananas are all true
Pocket PC Version - Expressions
Modus Ponens and Modus Tollens
Pocket PC Version - Tables
Assertion Table only shows rows in which all assertions are
true. Here is Modus Ponens from which only B true (0) can be
concluded.
Pocket PC Version – 4 Variables
Apples and Oranges
Several Variables with many
characters
The Assertion Table only lists
rows in which conjunction of
expressions is true.
What is Missing to Date?
Automated – Minimum User Input
2. Read Large Sets of Statements
3. Output Conclusions
4. Use Quantifiers – All, Some, None, …
1.

Requires Peirce’s Beta Model
What is Doable?
1.
Automated and Read Text Files



Hide Engine
Allow Manual Entry or Read Text
Parse words like “and”, “or”, “not”, “if .. then”
Last Two Features have recently been added!
Read Text Files
Create the Text File
Open File
Parse
Assert
Results:
•Red
- False (1)
•Blue
- False (1)
•Green - True (0)
•Yellow - False (1)
Expressions with “and”, “or”, “not”
Create Text File
But without symbols
Open File, Parse and
Assert
The Conclusions are
the same as before
Last Example
Enter and Add Two
Expressions
Assert
What can one
conclude?
Results:
•A
- ? (0 or 1)
•B - False (1)
•C - True (0)
What needs work
1.
Automate Conclusions


2.
May output simple combinations of statements
May need user input to determine what types of
combinations
Implement Peirce’s Beta/Gamma Logic


Alpha version is equivalent to Boolean Logic
Beta Version follows basic rules and free of user
creativity
Summary
We have a prototypical engine that can




Create truth tables
Parse simple statements
Can read in sets of statements from files
Check validity of non-quantified statement sets
We seek an engine that




Is more automated
Can treat quantifiers (all, some, none)
Can parse more complicated statements
Can make logical conclusions automatically
Thank you!
A copy of this presentation is located at
http://people.uncw.edu/hermanr/tech.htm
Questions and suggestions can be directed to
Dr. Russell Herman
Or
Dr. Pattricia Turrisi
hermanr@uncw.edu
turrisip@uncw.edu
UNC Wilmington, Wilmington, NC