Thanx!

reanie at netpoint dot co dot za]]>

I Kripke models, when they state "worlds accessible from x1" for example. Is that only worlds DIRECTLY connect to x1, or does it also include worlds you can access maby through another. For example x1 -> x2 -> x3.

Or if you look at figure 5.3 page 311. Is X6 accessible from x4?

Well, thanks guys, and good luck for the exam tomorow.]]>

K it seems to be abit hard to type the formula here. But basicly you need to draw a parse tree of the formula. The formula starts with 2 Quantifiers that quantifies the whole formula(rest of formula is all in brackets). But the tree starts with the --> Symbol, then the quantifiers. Shouldnt it be the other way around?

Id be very gratefull if somebody can clear this up for me.

Thanks]]>

Q1e) â€œCancer will not be cured unless its cause is determined

Answer

p: "The cause of cancer is determined"

q: "A new drug for cancer is found"

r: "Cancer will be cured"

The corresponding formula would be: (Â¬p A Â¬q) -> Â¬r

Alternatively, you can have Â¬ (p V q) -> Â¬r

Now I dont know why I am not getting this, but those answers seems to me like. "If no cause is determend AND no drug is found, cancer wont be cured"

Shouldnt it be OR? Since if either one isnt satisfied it wont be cured

the 2nd reads the same, but shouldnt that be a p AND q?

K onto the end question/answer which is Q5. prove the validity of (p->q)V(q->r) by LEMMA. Part of the answer is

7 Â¬q assumption

-------------------

8 q assumption

9 _ Â¬e 8,7 (_ is contradiction)

10 r _e 9

------------------

How can you just stick in the r? Where does that come from? So you assume q, but it contradicts q so we elliminate it and get r???? Please somebody, I cant get my head around that step. And unfortionatly the book hardly makes sense to me this year and the tutorial letters arent really a big help.

Appreciate any help guys. Thanks]]>

Also why are all the available tutorial letter downloads on osprey from 2005.]]>

No one struggling with this module? I know I am]]>

Is anyone willing to share previous years' tutorial matter incl solutions? It will help me understand the subject better.

Tx.]]>

I followed the instructions for installing the software faithfully. However, when I try to run QIde.bat from the desktop or the bin directory I get "Windows cannot find QIde.exe" etc.

I have checked the path and it is correct.

I have also searched for QIde.exe and it's not there. In fact it's not anywhere.

Any help will be much appreciated.

JoJ.]]>

Question 12 looks like it's asking us to prove De Morgan's theorem. Am I correct in this? Even then, I have no idea about how to tackle it.

Question 15: Drawing the DAG for a formula is not a problem, but how the heck do you draw a DAG for a sequent? Do you need to get it into a single formula? How do you do that?

Any tips would be most appreciated.]]>

I'm a little bit lost when it comes to Horn formulas. What exactly do they mean by "marking"? Could someone maybe provide a simple example of how to apply the HORN algorithm to a Horn formula so I can see it in action?

Thanks

Justin]]>

Does anyone know this stuff well enough to explain it?]]>

I wrote a bit of test code to check my answers, and have wasted an hour or so trying to figure out why my results didn't check out, only to realise that it was correct, just not in the right order.

(Also posted to the myUnisa discussion forum)]]>

No formal work experience is required, but candidate should have a good aptitude towards programming.

If interested, please send your CV to info@tshwanedje.com. Salary negotiable based on skills and experience. Starting ASAP.]]>