I am going to have to pull out of the meeting. I have been in hospital for 16 days, and need 5 more weeks of IV antibiotics but at home, so need a special line putting into my arm. This may take one or two days to complete. I will be unable to travel till Mid-November. Do we have any SIG dates for meetings in Crete that I can move my flight tickets to? Sent from Outlook for Android<https://aka.ms/AAb9ysg> ________________________________ From: Crm-sig <[email protected]> on behalf of Christian-Emil Smith Ore via Crm-sig <[email protected]> Sent: Monday, October 6, 2025 1:53:32 PM To: crm-sig <[email protected]> Subject: [Crm-sig] Issue 692 Inverse properties in FOL
Dear all, The original idea in Issue 692 "Inverse properties in FOL" was to get rid of the use if the 'i' notation indicating the use of the inverse of a given property, as for example in the definition of P2 (page 119): P2: This property is a shortcut for the path from E1 CRM Entity through P41i was classified by (classified), E17 Type Assignment, P42 assigned (was assigned by) to E55 Type. P2(x,y) ⇐ (∃z) [E17(z)] ∧ P41i(x,z) ∧ P42(z,y)] The suggestion was not welcomed by the SIG and as the example above shows it can be handy. The proposal is dropped and instead one should write a short text to be put into the introduction (the part about FOL formalism). Suggestion (addition marked with yellow at page 23): In contrast, first-order logic-based knowledge representation relies on a language for formally encoding an ontology. This language can be directly put in correspondence with semantic data modelling in a straightforward way: * classes are named by unary predicate symbols; conventionally, we use E21 as the unary predicate symbol corresponding to class E21 Person; * properties are named by binary predicate symbols; conventionally, we use P152 as the binary predicate symbol corresponding to property P152 has parent (is parent of). * properties of properties, “.1 properties” are named by ternary predicate symbols; conventionally, we use P14.1 as the ternary predicate symbol corresponding to property P14.1 in the role of. * Inverse of properties are indicated using an ‘i’ after the number. So P152i is parent of (has parent) is the inverse of P152 has parent (is parent of). In the First-Order representation the arguments are swapped so P152(x,y) is equivalent to P152i(y,x). The second part of the HW: to check if swapping arguments are used in the FOL axioms: P5: [P5(x,y) ∧ P5(y,z)] ⇒ P5(x,z) P5(x,y) ⇒ ¬P5(y,x) and all the other anti-symmetric ones. In my opinion it is ok to leave them as is. In the FOL for the fully developed paths only the inverse were used. Best, Christian-Emil
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