[Cs4800] Fwd: Unfair HW Assignment

[Karl Lieberherr]

Let's go over this in class tomorrow. I welcome this kind of anonymous
communication. As an alternative, you could send the message to Alex
and then he forwards it to me anonymously.

It is really not hard; Boolean CSP is very close to Satisfiability; indeed
some
people call it generalized satisfiability.

Shannon cofactor is just a fancy name for substituting one variable by a
truth value. We already used them when we went from SAT to FSAT.
But I did not use the fancy name.

256 = 2^8 because a Boolean relation of arity 3 has 8 rows in the truth
table.

More tomorrow.

-- Karl

---------- Forwarded message ----------
From: No Name <noname6589 at yahoo.com>
Date: Sun, Feb 21, 2010 at 3:58 PM
Subject: Unfair HW Assignment
To: lieber at ccs.neu.edu, karl.lieberherr at gmail.com


  The homework assignment that you have assigned for Wednesday is *
extremely *unfair.

We went over the material for no more than 1/2 of the lecture last Thursday
and in the assignment you mention things that were neither mentioned in
class nor are covered in the book.

Look at part 1:

Boolean CSP is a generalization of Satisfiability where the clauses are

defined in terms of a set of Boolean relations

Boolean CSP seems to be more deep that what you stated. This should be
explained in class.

while 3-CSP may use any

of the 256 Boolean relations of arity 3.

256 Boolean relations? How did you get this? This was never covered in class
either.
Consider F[x=0] and F[x=1] to be the two Shannon cofactors of F

so that the following recurrence holds:

F = (!x and F[x=0]) or (x and F[x=1])

What are *Shanon cofactors*? You never mentioned this word in your lectures
and it is not in the book. I have never heard of this in ANY of my other
Math or CS courses

Do you honestly expect us to learn all of this material on our own? We only
had 20 minutes of lecture on this material and you honestly expect us to be
able to solve the homework? I am sure that their are other members of the
class that feel the same way, they just do not want to say anything.

This is not fair.
-------------- next part --------------
HTML attachment scrubbed and removed