logic/readme.md
2025-08-12 07:56:27 +00:00

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# statement logic !!!
things that are in here:
### general statement things
#### [Logic/Statement/Parse.hs](Logic/Statement/Serialize.hs)
- parse string -> statement
- serialize a statement -> plaintext, LaTeX
#### [Logic/Language/Impl/L.hs](Logic/Language/Impl/L.hs)
- serialize a statement -> L (the formal language)
- parse L (the formal language) string -> statement
### semantic things (statements have meaning I guess)
#### [Logic/Statement/Eval.hs](Logic/Statement/Eval.hs)
- assign truth values and evaluate statements
- determine tautology, contradiction, or contingent
#### [Logic/Statement/Serialize.hs](Logic/Statement/Serialize.hs)
- generate a LaTeX truth table from a statement
#### [Logic/Statements/Laws.hs](Logic/Statements/Laws.hs)
- match/replace patterns in statements (e.g. logical laws)
- verify logical-law equivalence of statements (TODO)
- find logical-law equivalence of statements with breadth-first search (slow)
### syntactic things (statements are strings of symbols)
#### [Logic/Language.hs](Logic/Language.hs)
- implement formal languages (symbols, axioms schemas, and inference rules)
with a clunky api, see also
<https://en.wikipedia.org/wiki/Post_canonical_system>
### [Logic/Language/Derivation.hs](Logic/Language/Derivation.hs)
- verify derivations in formal languages
### formal languages implemented
- [the MIU system](Logic/Language/Impl/MIU.hs) (from "Gödel, Escher, Bach")
- [L](Logic/Language/Impl/L.hs)
### general things
#### [Logic/Parse.hs](Logic/Parse.hs)
- generic sequence parser
#### [Logic/Graph.hs](Logic/Graph.hs)
- generic breadth-first search
## requirements
a haskell compiler e.g. GHC
## compile it
```sh
make
```
or look in [`Makefile`](Makefile)
## usage
only this has been implemented in the main function:
```sh
echo '((p->q)<->(!q->!p))' | ./logic
```
### output
```
Iff (Implies (Atom "p") (Atom "q")) (Implies (Not (Atom "q")) (Not (Atom "p")))
Tautology
\begin{tabular}{cc||cccccc|c|cccccccc}
$p$ & $q$ & $($ & $($ & $p$ & $\to $ & $q$ & $)$ & $\leftrightarrow $ & $($ & $\neg $ & $q$ & $\to $ & $\neg $ & $p$ & $)$ & $)$ \\
\hline
0 & 0 & & & 0 & 1 & 0 & & \textbf 1 & & 1 & 0 & 1 & 1 & 0 & & \\
0 & 1 & & & 1 & 0 & 0 & & \textbf 1 & & 1 & 0 & 0 & 0 & 1 & & \\
1 & 0 & & & 0 & 1 & 1 & & \textbf 1 & & 0 & 1 & 1 & 1 & 0 & & \\
1 & 1 & & & 1 & 1 & 1 & & \textbf 1 & & 0 & 1 & 1 & 0 & 1 & & \\
\end{tabular}
```