Class For-Sale

Notes for For-Sale:

The defintion for For-Sale entails a necessary distinction between the seller (VENDOR) and the buyer (Potential Customer), in that only the former is offering something.
Representing For-Sale as a Class in this manner, is equivalent in meaning to modelling it as a ternary Relationship between one Legal-Entitiy and two Goods, Services, or Quantities of Money to be exchanged. This approach was chosen becauses it seemed simpler. It is an open question as to whether it makes much difference.

Arity: 1
Documentation:
A situation whereby one Legal-Entity offers to enter into a Sale. This necessarily entails a Product-For-Sale and an Asking-Price.
Domain-Of: Asking-Price, For-Sale-Vendor, Product-For-Sale, Specified-Potential-Customer
Instance-Of: Class, Relation, Set
Subclass-Of: Eo-Entity, Individual, Individual-Thing, Thing
Superclass-Of: Proposed-Sale-Offer

Asking-Price:: Slot-Cardinality: 1; Slot-Value-Type: Good-Service-Or-Money
For-Sale-Vendor:: Slot-Cardinality: 1; Slot-Value-Type: Legal-Entity
Product-For-Sale:: Slot-Cardinality: 1; Slot-Value-Type: Eo-Entity
Specified-Potential-Customer:: Minimum-Slot-Cardinality: 0; Slot-Value-Type: Legal-Entity

(<=> (Proposed-Sale-Offer ?X)
     (And (For-Sale ?X)
          (Exists (?Le) (Specified-Potential-Customer ?X ?Le))))