<div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div class="im"> > "If a card X1 is inserted then exactly X1 is inserted. ..." > exactly meaning that no other card is inserted. > > Is the last the most natural way to express xor in ACE for the example sentence? </div>No. Note that an exclusive or could be imbedded in an if-then sentence which would make your constructs very hard to read. </blockquote><div>I's evaluating several options with the editor, before reporting back. </div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> To express "A XOR B" in ACE you write – as you do in standard FOL – "(A and not B) or (B and not A), similar to what you did in your email of 10 July 2010 22:10:10 CEST. </blockquote><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> Or – and this is probably an exclusive or – you could add the exclusive or to ACE, download the Attempto Parsing Engine APE and extend it by grammar rules processing the exclusive or. </blockquote><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> <div class="im"> > --- unchanged since 25/1/10 --- > P.S. Unless a notification (LON), please reply either with an answer OR with " ACK" appended to this subject within 48 hours. Otherwise, I might resend. > In(LON, this) ∨ In(48h, TimeNow) ∨ ∃x. In(x, MyInbox) ∧ IsAnswerTo(x, this) ∨ (In(subject(this), subject(x)) ∧ In(ACK, subject(x)) ∧ ¬IsAnswerTo(x,this)) ⇒ ¬IResend(this). > > Also note that correspondence may be received only from specified a priori senders, or if the subject of this email ends with a code, eg. -LICHT01X, then also from senders whose reply contains it. > ∀x. In(x, MyInbox) ⇒ In(senderAddress(x), MySafeSenderList) ∨ (∃y. In(y, subject(this) ) ∧ In(y,x) ∧ isCodeLike(y, -LICHT01X) ). </div>What does this mean? --- nef </blockquote></div>So despite all attempts it's still ambiguous? I'll work on expressing it with Attempto, but the logic formulation should be equivalent. Predicates I used: In(x,y): x is in y. IsAnswerTo(x,y): x is an answer to y. IResend(x): I resend the email. isCodeLike(x,y): x is code like/similar to y. Constants: this: the email I've sent. 48h: the time at 48 hours from the time this was sent. TimeNow: the time now. MyInbox: my inbox. MySafeSenderList: a list of senders I reckon to be safe (i.e. they send emails I want to receive). Functions: subject(x): maps email x to its subject. -- Regards, K. Gabriele --- unchanged since 25/1/10 --- P.S. Unless a notification (LON), please reply either with an answer OR with " ACK" appended to this subject within 48 hours. Otherwise, I might resend. In(LON, this) ∨ In(48h, TimeNow) ∨ ∃x. In(x, MyInbox) ∧ IsAnswerTo(x, this) ∨ (In(subject(this), subject(x)) ∧ In(ACK, subject(x)) ∧ ¬IsAnswerTo(x,this)) ⇒ ¬IResend(this). Also note that correspondence may be received only from specified a priori senders, or if the subject of this email ends with a code, eg. -LICHT01X, then also from senders whose reply contains it. ∀x. In(x, MyInbox) ⇒ In(senderAddress(x), MySafeSenderList) ∨ (∃y. In(y, subject(this) ) ∧ In(y,x) ∧ isCodeLike(y, -LICHT01X) ).