1. Exercise 3 on page 154.
2. Exercise 4 on page 155.

• > Tell me what you know about 'animal', with justification.
  An animal is an organism; you told me that directly.
  An animal is a thing, because an animal is an organism and an organism is a thing.
  An animal is something more general than a mammal, because a mammal is an animal.
  An animal is something more general than a dog, because a dog is a mammal and an mammal is an animal.
  An animal is something more general than a fish, because a fish is an animal.
  That's all I know about 'animal'.
  

  The starter code includes a "test" feature that will give you some evidence about whether your program implements this feature correctly or not. This test feature was developed by A2 lead TA Connor Schenck.

• Cycle Detection and Elimination. Because the ISA relation is a partial order, it must obey the antisymmetry property, which states that if x R y and y R x, then x = y. Because of transitivity, this means than in any cycle, such as a R b, b R c, and c R a, it must be the case that a = b = c. When the user inputs statements that form such a cycle, your program should detect that a cycle would be formed by the latest statement, if processed normally. It should report that to the user and then perform the following changes to the database: Determine which node is the starting point in the cycle (for example x when x R y and y R x are input in that order). Make all the other nodes in the cycle become "aliases" of the starting node, and merge them into the starting node. That means any edge involving one of these nodes has one of its endpoints replaced by the starting node. The program should be able to use the aliases in further interactions. An example is given below.

  > A creature is a being.
  I understand.    
  > A being is a living-thing.
  I understand.    
  > A living-thing is a creature.
  I infer that creature, being, and living-things are all names
  for the same thing, and I'll call it creature.
  > A bug is a creature.
  I understand.
  > Is a bug a being?
  Yes.
  > Why is a bug a being?
  Because a bug is a creature, and being is another name for creature.
  > A living-thing is an organism.
  I understand.
  > Is a bug an organism?
  Yes.
  > Why is a bug an organism?
  Because a bug is a creature, and a creature is an organism.
  

Each student should Turn in a file PartI.txt and a file PartII.py.
Your PartI.txt file should contain your name and the answers to the questions in Part I. Your PartII.py file should begin with a multiline string that gives, on the first line, your name, and on the next line, an indication of whether you did the extra-credit option. Here is an example.

'''PartII.py
John Doe, CSE 415, Autumn 2017, University of Washington
Instructor:  S. Tanimoto.
Assignment 2 Part II.  ISA Hierarchy Manipulation
Extra credit (Cycle detection and processing) implemented and working.
'''

The rest of your file PartII.py should contain a version of the Linneus program that provides the implementation of the features according to your status comments.

If necessary, substantial updates and corrections will be posted here and mentioned in class or on GoPost.

After submitting your solution, please answer this survey