lecture16

# lecture16 - Homework 8.4AOddnumbersupto23...

This preview shows pages 1–6. Sign up to view the full content.

Homework 8.4 A Odd numbers up to 23 8.5. A Odd numbers up to 19. (Contrary to what the book says, you may  use CP and RAA in any of these  questions).

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Some Tips on Derivations We have 8 implication rules and 10 equivalence  rules.  I suggest using MP, MT, DS, HS and CD whenever  you can see the opportunity to do so. (The first three  will come up more frequently than the latter two) Use DeMorgan’s whenever you have the negation of  a conjunction or a disjunction on a line. Use ME whenever you have a biconditional on a line. Use the other rules only when you can see how they  will be of use.
A couple of proofs ~U  → ~B, S → ~B, ~(U ● ~S), T v B . ˙. T ~(J  ● L), (J → ~L) → (~M ● ~X), E v (M v X) .˙. E

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Conditional Proof The method we have been using so far is called  direct  derivation . With this method you go directly from the premises  to the conclusion. We are not able to construct a direct derivation for every valid  argument. For example, it’s not possible to construct a  derivation for: → ~B .˙. F → (F ● ~B) So we’re going to learn a new method which will make our system complete. This method will also make it easier to derive conditionals, and make many proofs more intuitive. It is called conditional proof .
Conditional Proof We know that conditionals assert that  if  the  antecedent is true, the consequent is true too. This suggests a method for deriving conditionals:

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 17

lecture16 - Homework 8.4AOddnumbersupto23...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online