November 6, 2006
Version 1.3 of BB1 released. Couple of bug fixes. New versions of semLexHole.pl, alphaConversion.pl, betaConversion.pl and betaConversionTestSuite.pl.
November 5, 2006
Arguments are swapped in the macro for transitive verbs in semLexHole.pl in version 1.2 of BB1. Corrected macro:
```
semLex(tv,M):-
   M = [symbol:Sym,
        sem:lam(Z,lam(X,app(Z,lam(Y,lam(H,lam(L,and(pred2(L,Sym,X,Y),leq(L,H))))))))].
```
Reported by Mike White.
November 17, 2005
Added link to interview with Patrick Blackburn in PhiNews

September 9, 2005
Discovered bug in alphabeticVariants/2. Some formulas with identical free variables were wrongly classified as non-alphabetic variants. The revised code for this predicate is:

alphabeticVariants(Term1,Term2):-
   alphaConvert(Term1,[],[]-Free1,Term3),
   alphaConvert(Term2,[],[]-Free2,Term4),
   Free1==Free2,
   numbervars(Free1,0,N),
   numbervars(Term3,N,M),
   numbervars(Term4,N,M),
   Term3=Term4.

September 8, 2005
There appears to be a bug in betaConvert/3. For input such as app(app(X,Y),Z) it returns no rather than succeeding and returning the same term. The current solution is this code:

betaConvert(X,Y,[]):-
   var(X), !,
   Y=X.

betaConvert(Expression,Result,Stack):-
   nonvar(Expression),
   Expression = app(Functor,Argument),
   alphaConvert(Functor,Converted),  
   betaConvert(Converted,Result,[Argument|Stack]), !.

betaConvert(Expression,Result,[X|Stack]):-
   nonvar(Expression),
   Expression = lam(X,Formula),
   betaConvert(Formula,Result,Stack), !.

betaConvert(Formula,Result,[]):-
   nonvar(Formula), !,
   compose(Formula,Functor,Formulas),
   betaConvertList(Formulas,ResultFormulas),
   compose(Result,Functor,ResultFormulas).

betaConvert(Exp,app(Exp,Y),[X]):-    
   betaConvert(X,Y).

Thanks to Sebastien Hinderer and Carlos Areces for reporting this.

August 8, 2005
Version 1.2 of BB1 released. Deals with the problem of numbervars in fol2otter.pl, fol2bliksem.pl, fol2tptp.pl, and comsemPredicates.pl. Also fixed a bug to do with equality in backgroundKnowledge.pl.
July 9, 2005
There is a problem with numbervars when using newer versions of SWI Prolog. Thanks to John Rood for reporting this.
June 10, 2005
Version 1.1 of BB1 released. Major changes in the perl programs.
March 15, 2005
Representation and Inference now available at CSLI publications.