# Logic System Interrelationships

Relationships between logic systems.

The structures pages show how a number of representative logics fit together. The interrelationships usually given as something of the form: System X is system Y plus the axiom Z.

Sometimes the complete axiomatic basis (or several) are given.

I personally believe that these are getting to the point of being a useful research tool for at least modal logics.

I welcome any and all feedback (even negative) on these pages.

Modal and other Logic System Interrelationships

# Expression Evaluator

This program uses standard predicate calculus with the usual connectives, and quantification over predicates of some small example worlds.

In it's limited world it can tell whether or not an expression is always true, always false, or can be both. In cases where it can be both, the program gives a set of values that make it true, and a set of values for which it is false.

To aid beginning students studying logic, if a top-level universal quantification is false, it shows the objects for which it is false. If a top-level Existential quantifier is true, the program shows the list of objects for which it came out true.

# Three valued modal logic Expression Evaluator

This program uses standard predicate calculus with the usual connectives, but evaluates expressions in a three valued modal logic. (At the moment Thad Coons' truth tables are being used, but hopefully I'll get time to add others. I'm open to suggestions of which might be worth while.

# Check Modal System Extensions

A program to help investigate extensions of Modal Logics with finite distinct modalities.

# Logic Calculator

Program to handle a lot of the diddly work of producing an Axiomatic proof.

It has a choice of several output notations and systems.

It uses the same input notation as the Expression Evaluator.

# Logic drills

[Under construction] [As if I'm ever going to get time to finish it.

# musings

Random thoughts. These are probably not worth reading at the moment.