Help with Or Elimination and Bi-conditional Introduction
Or Elimination and Bi-Conditional Introduction
12/23/05
Or Elimination
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12/23/05
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2013
Learning the Rules Or Elimination and the Introduction of the Biconditional.
Bergmann[2008] The Logic Book Section 5.1 and 5.4
Or Elimination, in the guise of Dilemma, also is a form of inference dating from antiquity.
Learning reductio proof, both as plain Negation Introduction and via (double) Negation Elimination (to prove some formulas that do not have negation as their main connective).
Bergmann[2004] The Logic Book Section 5.1 and 5.4
Reductio ad Absurdum is the second of the classical forms of inference.
9/12/06
This video shows the techniques for Conditional Proof using the downloadable application Deriver. But the techniques are exactly the same for the Proof applet running in a web page. So, the video may look slightly different to what you are looking at, but the underlying principles and approach are the same.
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2013
Learning conditional proof.
Bergmann[2008] The Logic Book Section 5.1 and 5.4
The five remaining sentential rules of inference are slightly more difficult than the ones that we have met before. They are slightly more difficult in that they require you to make new assumptions, and the correct new assumptions at that. However they follow a similar pattern to each other so mastery of one should lead to mastery of the others.
2013
This movie shows the downloadable application being used, but the manipulations are so similar to those of the web page applet that it really covers both.
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2013
Proving an argument to be valid by displaying a derivation. Simple propositional derivations using some of the Rules of Inference.
Bergmann[2004] The Logic Book Section 5.1.
If you suspect that an symbolized argument might be valid, you should attempt to give a derivation of it.
A derivation is a proof of validity.
Review of new material
There are the truth-tables for the connectives...
Negation
F ∼F True False False True
Conjunction
1/7/13
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