Re: ISSUE-82 (Unification): Shall Core limit unification to pattern matching (as PRD does)? [Core]

Christian de Sainte Marie wrote:
> 
> Gary Hallmark wrote:
> 
>> [...]
>>
>> RS3:
>> ex:A(2)
>> ex:A(?x) :- ex:A(?y), ?y + 1 = ?x
>>
>> [...]
>> RS3 is unsafe, so if PRD adopts Core safety then RS3 would not be in 
>> PRD, even though it poses no problems.
> 
> Is RS3 unsafe? Is it because = is meant as pred:numeric-equal? But it 
> poses no problem from the logic point of view either, right?

RS3 is supposed to be safe, ?y occurs in a plain atomic formula.

Though looking at the current definition of safeness we don't seem to 
have covered equals properly.

Dave