Rob, thank you very much for answering my questions! That was smart of you to notice this problem, which I have worried about:
your axioms seem to be loose about whether `(A, B) same_side l` holds if A or B is on the line l. I like your EquivRelOn R P solution (thanks for the correction), or we can even define EquivRelOFF R I. I have two more questions. 1) Can you tell me why this didn't work? let SameSideEquivalenceRelation_THM = thm `; thus Reflexive_Property /\ Symmetric_Property /\ Transitive_Property proof qed by SameSideReflexiveRelation_THM, SameSideTransitiveRelation_THM, SameSideTransitiveRelation_THM, Reflexive_relation_DEF, Symmetric_relation_DEF, Transitive_relation_DEF `;; I just got the error ::#2 inference time-out. I imagine I'll have the same problem with your code. Maybe this is the wrong way to go about proving that some relation is an equivalence relation. 2) I wrote a new definition I have a definition let InteriorAngle_DEF = new_definition `!A O B. int_angle(A, O, B) = if Collinear(A, O, B) then {} else {P | ~(P IN line(O, A)) /\ ~(P IN line(O, B)) /\ P,B same_side line(O, A) /\ P,A same_side line(O, B)}`;; I don't if it's working yet, but I would like to simplify this with a variable declaration and then substitution a = line(O, A) b = line(O, B) You must know how to do that. -- Best, Bill ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ hol-info mailing list hol-info@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/hol-info