CSci 431

Exercise set #4

Due:  Wednesday, Oct. 30 (in class)

Please work problems 6.1, 6.2, and 6.5 on pages 180 - 181  of the textbook.

Please work the following two using resolution (from Wilfrid Hodges: Logic, Penguin 1977)L

• If the driver was in control, then he passed the signal if and only if it was green.  The driver passed the signal, although he was in control.  Only if the electronic were faulty was the signal green.  Therefore the electronics were faulty (careful about the only if clause).
• Either the vicar or the butler shot the earl.  If the butler shot the earl, then the butler wasn't drunk at nine o'clock.  Unless the vicar is a liar, the butler was drunk at nine o'clock.  Therefore either the vicar is a liar, or he shot the earl.

This exercise set should be turned in in class on Wednesday, Oct. 30.

Any questions? Please ask!