code for unevaluated Boolean and conditional express ions

> -----Original Message-----
> From: BIOMATES at telefonica.net [mailto:BIOMATES at telefonica.net] 
> 
> Either cat fur or dog fur was found at the scene of the crime. If dog
> fur was found at the scene of the crime, officer Thompson had an 
> allergy
> attack. If cat fur was found at the scene of the crime, then Macavity 
> is
> responsibile for the crime. But officer Thompson didn't have an 
> allergy
> attack, and so therefore Macavity must be responsible for the crime.
> 
> 
> Now, let's define some variables:
>    p: cat fur was found at the scene of the crime,
>    q: dog fur was found at the scene of the crime,
>    r: officer Thompson had an allergy attack,
>    s: Macavity is responsible for the crime
> 
> 
> Premise #1: p or q
> Premise #2: q => r
> Premise #3: p => s
> Premise #4: not r
> 
> Question: is Macavity responsible for the crime?
> 
> /**********  begin Maxima session ********/
> 
> (%i1) load("~/Desktop/boolsimp.lisp")$
> (%i2) /* I define the conditional operator */
>       "=>"(r,s):= not r or s $  infix("=>") $
> (%i4) /* Checks for the validity of */
>       /* ante => conse by means of  */
>       /* the truth table.           */
> implies(ante, conse, listvar):=
>   block([expr,npos,maxn,combis:[],bits,quot,div],
>     npos: length(listvar),
>     maxn: 2^npos - 1,
>     expr: not ante or conse,
>     for i:0 thru maxn do(
>       bits:[],
>       quot:i,
>       for j:1 thru npos do(
>         div: divide(quot, 2),
>         quot: div[1],
>         bits: cons(listvar[j]=div[2],bits) ),
>       combis: cons( subst([1=true,0=false],bits), combis)),
>     apply("and", makelist(subst(k,expr),k,combis))  )$
> (%i5) /* Let's know who's the criminal */
>       implies((p or q) and (q => r) and (p => s) and not r,s,
>               [p,q,r,s]);
> (%o5)                   true
> 
> /**********  end Maxima session ********/
> 
> Lawyers will find your 'boolsimp' package very useful !
> 
Can we make it part of the BAR exam?
Could we make our politicians take it?  Sort of a politician poll test.
(from the USA)

RRogers