CIS 554 Assignment 1: Logic Puzzles

Fall 2011, David Matuszek

- To give you some experience with logic programming.
- To introduce lists in Prolog.
- To emphasize the
*declarative*nature of Prolog. (The entire program consists of a*statement*of the problem,*not*some algorithm to solve the problem.)

Solve two standard (commercial) logic puzzles.

I am providing three such puzzles:

**It's a Tie**-- I have provided a sample solution for this one. Use this as a model for your own solutions.**Imaginary Friends**-- The first part of your assignment is to write (and turn in) a Prolog program to solve this logic puzzle. Once you understand the "It's a Tie" solution, this should be easy. Do this one first.**Star Tricked**-- The second part is to write (and turn in) a Prolog program to solve this logic puzzle. This one is a little trickier--you need to figure out how to describe the ordering of weekdays--but it's not too hard..

**Notes:**

- Use SWI-Prolog for this assignment (and the next).
- Here's an (old) Concise Guide to Prolog which I wrote up. Still accurate, but not very pretty.
- One of my problems in solving these was spelling errors. Prolog checks for singleton variables, but there is no such check for misspelled atoms, such as
`spiegel`

instead of`speigel`

. Be especially careful of this. - These problems make unusually extensive use of the "not" operator,
`\+`

. Here's what you need to know about this operator:`\+`

works as you would expect when all variables are completely instantiated (bound).- Prolog tries to prove things, so if expression E contains unbound variables,
`\+E`

will try to find variable bindings that will make E true.

- It is easy to check whether a solution is correct: Just check whether it satisfied each of the numbered rules in the problem.

This one should be easy to grade; your program should produce the correct solution. We may deduct points if your formatting is egregiously bad.

` .pl`

files, along with a file containing the two solutions (copy from the output area and paste them into a text file). Note that I require a