hausman

Quiz 7 Invalidity

6/19/09

Quiz 7 Invalidity

[This has been done in the downloadable application, but the principles apply to the applet version also.]

Quiz 7 Invalidity

6/19/09

Quiz 7 Satisfiability

6/19/09

Quiz 7 first few tabs

[This has been done in the downloadable application, but the principles apply to the applet version also. This video also calls the Quiz, 'Quiz 4'.]

Quiz 7 Satisfiability

6/19/09

12/25/06

Introduction to Free Variables

This video illustrates use of the downloadable application (and the symbol ∧ for 'and' and (∀x) for the universal quantifier, some systems use (x) for this). But, what the film depicts and explains is equally good if you happen to be using the web pages applets (or different symbols for 'and' and the universal quantifier).

6/18/07 10 Software

Skill to be acquired in this tutorial:

To learn how to use the Universal and Existential Quantifiers in symbolizing propositions.

Reading

Hausman[2007] Logic and Philosophy Chapter 7

The Tutorial

In Predicate Logic there are two new logical connectives, the Universal Quantifier (x) and the Existential Quantifier (∃x). These are used for symbolizing certain English constructions (they also have their own rules of inference and their own semantics, which we will learn about later).

10 Software

Reading

Hausman[2007] Logic and Philosophy Chapter 8

The Tutorial

A few concepts are needed give a simple portrayal of the truth and falsity of predicate logic formulas.

There is the notion of an Interpretation which consists of a Universe together with an account of how the various symbols in the predicate logic formulas apply in this Universe.

There should be a Universe, which is the collection of the objects that the formulas is about. We write, for example,

Universe = {a,b,c}

6/6/09 10Software

Skill to be acquired:

To learn how to interpret simple predicate logic formulas as being true or false.

Why this is useful:

This helps in proving invalidity by the technique of displaying a counter-example.

Reading

Hausman[2007] Logic and Philosophy Chapter 8

The Tutorial:

In sentential logic, we just took it that each of the atomic sentences either is true or is false-- we did not look into the structure of the sentences.

Truth can be discussed in more detail in predicate logic.