Autosave: 2022-12-21 08:30:01

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thomasabishop 2022-12-21 08:30:01 +00:00
parent 852d2a2bad
commit 6e39cefb42
3 changed files with 16 additions and 34 deletions

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@ -42,20 +42,12 @@ $$
$ \{P, Q\} $ form a consistent set because there is at least one assignment when both propositions are true. In fact there are two (corresponding to each disjunct) but one is sufficient.
```
P Q P Q Q
T T T T *
T F T F
F T T T *
F F F F
```
| $P$ | $Q$ | $ P \lor Q $ | $Q$ |
| --- | --- | ------------ | --- |
| 0 | 0 | 0 | 0 |
| 0 | 1 | 1 | 1 |
| 1 | 0 | 1 | 1 |
| 1 | 1 | 1 | 1 |
| T | T | T | T |
| T | F | T | F |
| F | T | T | T |
| F | F | F | F |
## Derivation

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@ -22,28 +22,19 @@ $$
### Truth-tables
```
P Q P ⊃ Q
T T T
T F F
F T T
F F T
```
```
P Q ~ P Q
T T T
T F F
F T T
F F T
```
| $P$ | $Q$ | $ P \supset Q $ | $ \sim P \lor Q$ |
| --- | --- | --------------- | ---------------- |
| T | T | T | T |
| T | F | T | F |
| F | T | T | T |
| F | F | F | T |
### Derivation
> Propositions $P$ and $Q$ are equivalent in a system of [derivation](Formal%20proofs%20in%20propositional%20logic.md) for propositional logic if $Q$ is derivable from $P$ and $P$ is derivable from $Q$.
Note that the property of equivalence stated in terms of derivablity above is identical to the derivation rule for the [material biconditional](Biconditional%20Introduction.md):
Note that the property of equivalence stated in terms of derivablity above is identical to the derivation rule for the [material biconditional](/Logic/Proofs/Biconditional_Introduction.md):
![bi-intro.png](../img/bi-intro.png)
![bi-intro.png](/img/bi-intro.png)
//TODO: Add demonstration of this by deriving two equivalents from one of DeMorgan's Laws

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@ -44,8 +44,7 @@ P
### Truth-table
```
P P
T T
F F
```
| $P$ | $P$ |
| --- | --- |
| T | T |
| F | F |