Jan wrote -- > I would assume a rel b rel c is almost the same as a rel b and b rel c > (where rel is a relation).
Yes, so would I but only when 'rel' is transtive. If I saw this notation used for a non-transitive relation without a good explanantion then I would suspect that the writer knows little about what she/he wrote and certainly not what this notation typically means. > The use and meaning I can see is formula manipulation. When solving an > exercise by formula manipulation, one would use n-ary relation symbols > (for example (x+1)^2=(x+1)*(x+1)=x^2+x+x+1=x^2+2x+1). > This is semantically different from a system of exercises: 3=x and x=2 > would never be written as 3=x=2. This nicely illustrates that it is only use of = as a transitive relation on a well-deduced set that can really survive this extension. In this non-transitive (and non-symmetric) use of = for assigment of a value, I would ask what does 3=x mean? chris _______________________________________________ Om3 mailing list [email protected] http://openmath.org/mailman/listinfo/om3
