Tuesday, February 24, 2009

*Important change to homework 2*--a new problem added and due date extended to 3/5 (!)


 I added part 4 to the homework to cover the propositional logic discussion. It is now due on 3/5

The rationale is that your midterm will cover all topics from homework 1 and 2. I will make the solutions for homework
available on 3/5.


ps: Here is what is added:

Part 4(Added new):
  • Consider the following inference rule: if we know A V B; and we know ~A, we can derive B. Show that this inference is sound using truth-table method. Is this inference complete? Can you show that this is a special case of resolution?
  • (Problem 7.9 from the text book) Given the following, can you prove that the unicorn is mythical? How about magical? Horned?
    "If the unicorn is mythical, then it is immortal, but if it is not mythical, then it is a mortal animal. If the unicorn is either immortal or a mammal, then it is horned. The unicorn is magical if it is horned."

1 comment:

  1. Re the unicorn problem- I just noticed the wording is a little different in the book than on the blog post. The blog says "but if it's not mythical, then it's a mortal ANIMAL." The book says "but if it's not mythical, then it's a mortal MAMMAL".


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