Ass1-Question 6: Missing symbols

Assignment 1, Question 6 as shown in tutorial letter 104 has missing symbols.The only errata which is there in Question 6 of tutorial letter 101 is b=d, otherwise everything else remains the same. So the whole question should read:

Is the sentence ¬Cube (b) a logical consequence of ¬(Tet (d) v b=d) and Cube (b) v Tet(d)?. Is it a tautological consequence? Justify your answers with reference to the truth table you construct.

My apologies.


Lecturer

I'm a bit lost with the logical consequence. I dont understand the example on page 111 how the show that Not every logical consequence of a sentence is a taotological consequence of that sentence. Please Help!
my email is: giggsmaca2@hotmail.com

Fighter 53

@giggs Not sure if I'm right but this is how I understand it.

When you draw the truth table, you can put a=b, b=c and a=c as reference columns (the columns on the left). When you do that you will have a situation where (a=b /\ b=c) is false but a=c is true, so it isn't a tautological consequence.

Here is the truth table. Notice row 2 is true for 1 but false for 2.

Next time you should probably create a new thread for your question, you'll probably get an answer quicker.