Lecture #15 started to look at propositional logic. In particular it introduced the idea of logic, propositions, and the basic syntax and semantics of propositional logic.

Notes are available in four formats:

- 1 slide per page, Postscript.
- 1 slide per page, PDF.
- 4 slides per page, Postscript.
- 4 slides per page, PDF.

The lecture covered broadly the same material as Chapter 13 of the textbook. However, the approach was rather different, and you may well want to leave looking at Chapter 13 until after the next lecture or two.