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Fig. 5 Value exchanges
The third component of a value exchange is the evidence document [ 1] . A trans-
fer may include some evidence document that certifies that the buyer has certain
rights on a resource. Typical examples of evidence documents are movie tickets that
certify that their owner has the right to watch a movie or hotel vouchers that make
the owner of the voucher eligible for accommodation at the hotel that issued the
voucher. In some cases it is sufficient to be the bearer of an evidence document to
use the rights it refers to, but in other cases these rights only hold for a specific
person stated in the document.
Summarizing, see Fig. 5 (which is drawn on the operational level), a value
exchange can be seen as combining three components:
The rights the buyer obtains on the resource, e.g., the ownership of a book;
The custody of the resource, e.g., the delivery of a book to the buyer;
The evidence document , e.g., a receipt that can be used to prove ownership of a
book.
While the first component, the rights, is always considered, the last two compo-
nents are optional. For example, when buying a piece of land, the buyer is typically
not given the custody of that resource. Clearly, evidence documents are not always
provided and, furthermore, the provision of custody and evidence documents may
be so trivial that it is not of interest to make them explicit. In some complex cases,
however, a more detailed analysis is called for since modeling only the transfer of
ownership in a value exchange is not sufficient to address important aspects of how
value is created and exchanged.
4 Designing Rich Value Models
Most languages for value modeling, including e3value, give meaning to value
exchanges by focusing on the transfer of ownership. However, as shown in the pre-
vious section, there are also other kinds of rights relevant for value exchanges as
 
 
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