Assignment #1: Logic I

  • Name:Lan Vu

  • Date:

  • Course ID: CSC 5682

  • Semester:Fall 2007

Simulation of the MIU system that shows the variety of strings that can be produced starting from any well formed axiom, such as MI.

The computer simulation of MIU System is shown in below interface. It is implemented in C++ language NET Framework 2.0.

Click here for full source code of this program.

1.    Why is the MIU System called typographical?

 

The MIU System is called typographical because this system uses its typographical rules for deduction to produce variety of strings from basic symbol M, I, and U.

 

Deduction using these rules in the MIU System is same with some operations found in a typographical system defined in GEB:

(1) Reading and recognizing any of a finite set of symbol

(2) Writing down any symbol belonging to that set

(3) Copying any of those symbols from one place to another

(4) Easing any of those symbol

(5) Checking to see whether one symbol is the same as another

(6) Keeping and using a list of previous generated theorems

 

 

2.    How does the MIU System use deduction?

 

Starting from any well formed axiom, such as MI, MIU system uses its rules for deduction. After each time of applying rules on current theorems, the system creates new strings derived from given axioms and they become new theorems. Deduction continues until the expected theorem is proved.

 

 

3.    Does the MIU System use induction in any way?  Explain.

 

The MIU system does not use induction in any way because the theorem to be proved is a specific one, not in general form. Moreover, this expected theorem may not be proved by applying such rules of MIU System.

 

 

4.    Explain any realistic interpretation of the symbols, or strings of symbols, in the MIU System.

 

I find no realistic interpretation of the symbols, or strings of symbols, in the MIU System because they have no meaning.

 

5.    Explain how conflict resolution is implemented in your simulation.

 

During the deduction process, rules applied by prior order rule 1 à rule 2 à rule 3 à rule 4. If rule 1 doesn’t work, rule 2 is tried.  

 

6.    Does your implementation of the MIU System use forward or backward chaining?  Explain.

 

My implementation of the MIU System use forward chaining. With a start string, the system will apply MIU System’s rules to create new strings until the target string is found.

 

7.    The MU Puzzle: Given only the axiom MI, is MU deducible in the MIU System?

 

The answer is no.

 

8.    Provide a convincing argument that MU is, or is not, deducible by the MIU System given only the axiom MI to start with.

 

According to Wikipedia, MU is not deducible by the MIU System given only the axiom MI to start with.None of the rules allows us to create a string whose total number of Is is a multiple of three, except by starting with another such string. Since we can only start with MI which contains one I, we can never produce such a string. In particular, we can never produce a string containing no Is, such as MU.

To see this, notice that the only rule which allows us to add "I"s to our string is rule 2, which will double the number of "I"s in the string, while the only rule which allows us to remove "I"s from our string is rule 3, which will remove 3 "I"s from the string.

Thus, the total number of "I"s in a string must be of the form 2a – 3b, where a and b are constants, and i is the number of "I"s in our axiom.

Retrieved from "http://en.wikipedia.org/wiki/MU_puzzle"

 

9.    Explain the relationship between the results of your simulation and automated theorem proving.  For example, how would the computer know if it was getting closer to proving the theorem or just spinning its wheels?

 

In my stimulation, goal search are expanded all branches of tree, so all possible rules applied to produce new strings. Search process will stop if target is found or limitation of search level is reach. I don’t determine how getting closer to proving the theorem.

 

References

1. The GEB book: http://tal.forum2.org/geb

2. Course Materials.

3. See the web references on the Links page of course website.

4. http://en.wikipedia.org/wiki/MU_puzzle (gives a solution to the MU puzzle).