Foundations of Artificial Intelligence Homework 3




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CSCI-561 – Foundations of Artificial Intelligence
Homework 3

This is a programming assignment. You will be provided with sample inputs and outputs (see
below). Please understand that the goal of the samples is to check that you can correctly parse
the problem definition and generate a correctly formatted output. The samples are very simple
and it should not be assumed that if your program works on the samples it will work on all test
cases. There will be more complex test cases and it is your task to make sure that your program
will work correctly on any valid input. You are encouraged to try your own test cases to check
how your program would behave in some complex special case that you might think of. Since
each homework is checked via an automated A.I. script, your output should match the example
format exactly. Failure to do so will most certainly cost some points. The output format is simple
and examples are provided. You should upload and test your code on, and you
will submit it there. You may use any of the programming languages provided by
Your code will be tested as follows: Your program should take no command-line arguments. It
should read a text file called “input.txt” in the current directory that contains a problem
definition. It should write a file “output.txt” with your solution. Format for files input.txt and
output.txt is specified below. End-of-line convention is Unix (since vocareum is a Unix system).
The grading A.I. script will, 50 times:
– Create an input.txt file, delete any old output.txt file.
– Run your code.
– Compare output.txt created by your program with the correct one.
– If your outputs for all 50 test cases are correct, you get 100 points.
– If one or more test case fails, you lose 2 points for each failed test case. (note that one
test case involves several answers in this HW; if any answer on a given test case is wrong,
then the whole case is counted as wrong).
Note that if your code does not compile, or somehow fails to load and parse input.txt, or writes
an incorrectly formatted output.txt, or no output.txt at all, or OuTpUt.TxT, you will get zero
points. Please test your program with the provided sample files to avoid this. You can submit
code as many times as you wish on vocareum, and the last submitted version will be used for

Project Description
RipeApe pharmacy is developing a self-service automated system to alert customers about
potential drug interactions for both prescription and over-the-counter drugs. Many medications
should not be taken together or should not be taken if a patient has certain symptoms and
allergies. Evaluating all the criteria for whether a patient can take a particular medication requires
the patient’s medical history and expert knowledge from a health care provider. The system,
however, can provide an instant guideline to keep patients informed and minimize the risks.
You are assigned by RipeApe to develop a beta version of the system using the first order logic
inference. Patient history and drug compatibility data will be encoded as first order logic clauses
in the knowledge base. The program takes a query of new drug list and provide a logical
conclusion whether to issue a warning.
You will use first-order logic resolution to solve this problem.
Format for input.txt


The first line contains an integer N specifying the number of queries. The following N lines contain
one query per line. The line after the last query contains an integer K specifying the number of
sentences in the knowledge base. The remaining K lines contain the sentences in the knowledge
base, one sentence per line.
Query format: Each query will be a single literal of the form Predicate(Constant_Arguments) or
~Predicate(Constant_Arguments) and will not contain any variables. Each predicate will have
between 1 and 25 constant arguments. Two or more arguments will be separated by commas.
KB format: Each sentence in the knowledge base is written in one of the following forms:
1) An implication of the form p1 ∧ p2 ∧ … ∧ pm ⇒ q, where its premise is a conjunction of
literals and its conclusion is a single literal. Remember that a literal is an atomic sentence
or a negated atomic sentence.
2) A single literal: q or ~q
1. & denotes the conjunction operator.
2. | denotes the disjunction operator. It will not appear in the queries nor in the KB given as
input. But you will likely need it to create your proofs.
3. = denotes the implication operator.
4. ~ denotes the negation operator.
5. No other operators besides &, =, and ~ are used in the knowledge base.
6. There will be no parentheses in the KB except as used to denote arguments of predicates.
7. Variables are denoted by a single lowercase letter.
8. All predicates (such as HighBP) and constants (such as Alice) are case sensitive
alphabetical strings that begin with uppercase letters.
9. Each predicate takes at least one argument. Predicates will take at most 25 arguments. A
given predicate name will not appear with different number of arguments.
10. There will be at most 10 queries and 100 sentences in the knowledge base.
11. See the sample input below for spacing patterns.
12. You can assume that the input format is exactly as it is described.
13. There will be no syntax errors in the given input.
14. The KB will be true (i.e., will not contain contradictions).
Format for output.txt:
For each query, determine if that query can be inferred from the knowledge base or not, one
query per line:

Each answer should be either TRUE if you can prove that the corresponding query sentence is
true given the knowledge base, or FALSE if you cannot.
Notes and hints:
– Please name your program “” where ‘xxx’ is the extension for the
programming language you choose. (“py” for python, “cpp” for C++, and “java” for Java).
If you are using C++11, then the name of your file should be “homework11.cpp” and if
you are using python3 then the name of your file should be “”.
– If you decide that the given statement can be inferred from the knowledge base, every
variable in each sentence used in the proving process should be unified with a Constant
(i.e., unify variables to constants before you trigger a step of resolution).
– All variables are assumed to be universally quantified. There is no existential quantifier
in this homework. There is no need for Skolem functions or Skolem constants.
– Operator priorities apply (negation has higher priority than conjunction). There will be
no parentheses in the sentences, other than around arguments of predicates.
– The knowledge base is consistent.
– If you run into a loop and there is no alternative path you can try, report FALSE. An
example for this would be having two rules (1) A(x) = B(x) and (2) B(x) = A(x) and
wanting to prove A(John). In this case your program should report FALSE.
– Note that the KB is not in Horn form because we allow more than one positive literal. So
you indeed must use resolution and cannot use generalized Modus Ponens.
Example 1:
For this input.txt:
Take(x,Warfarin) = ~Take(x,NSAIDs)
your output.txt should be:
Example 2:
For this input.txt:
Take(x,Warfarin) = ~Take(x,NSAIDs)
HighBP(x) = Alert(x,NSAIDs)
your output.txt should be:
Example 3:
For this input.txt:
Migraine(x) & HighBP(x) = Take(x,Timolol)
Take(x,Warfarin) & Take(x,Timolol) = Alert(x,VitE)
your output.txt should be:
Disclaimer: Examples and test cases are for the purpose of testing logic inference in this
homework only. They do NOT represent factual information on drug interactions.