There are 34 relationships defined in LRM. This is not a closed list: 
"Any additional relationships needed by a particular implementation can 
be defined as sub-types of the additional relationships defined in the 
model, or of the top relationship." (p. 45)

However, I am bewildered by what seems to me a discrepancy between very 
general and very specific relationships in the list. The selection of 
relationships defined seems to me somewhat arbitrary and not really well 
balanced. I would prefer to have more relationships on a middle level of 
the hierarchy.

For example, sometimes we find very detailed relationships. Look at 
LRM-R26 (Manifestation - has reproduction/is reproduction of - 
Manifestation) and LRM-R27 (Manifestation - has alternate/has alternate 
- Manifestation). If we compare this to RDA, we find the element 
"Related Manifestation" (RDA 27.1) on the highest level. Then there is, 
in appendix J.4.2, "equivalent (manifestation)" with several sub-terms, 
among them "reproduced as (manifestation)/reproduction of 
(manifestation)" and  "also issued as". So, the RDA equivalents of 
LRM-R26 and R27 are on the third (!) hierarchical level. However, there 
is no general relationship defined between two manifestations in LRM 
(something like: Manifestation - is associated with/is associated with - 
Manifestation". I think this is rather amazing for a model which claims: 
"In the FRBR-LRM model, the relationships are declared in a general, 
abstract way and thus enable implementers to include additional details 
in a consistent and coherent way by introducing additional types." (p. 43).

Another example are the relationships between two agents. Again we find 
some rather specific relationships (e.g. Agent - is member of/has member 
- Collective Agent), but no general relationship between two agents. 
Therefore, if we want to express that person A is married to person B by 
using the relationships defined in LRM, we need to fall back on the most 
general relationship, FRBR-LRM1 (Res - is associated with/is associated 
with - Res), as there is no specific relationship which could be used. I 
would much prefer LRM to have, for every entity, a general relationship 
between two entities of the same kind, e.g. "Work to Work", "Expression 
to Expression", "Agent to Agent" a.s.o.

A second point which struck me when looking through the list of 
relationships: Why is there no whole/part relationship for Item? 
Whole/part relationships are defined for 7 out of 11 entities. I do 
understand that a whole/part relationship doesn't make much sense for 
Person, which in turn means that it cannot be defined for the 
hiearchically superior entities Agent and Res. But I am at a loss why it 
wasn't defined for Item.

Heidrun

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Prof. Heidrun Wiesenmueller M.A.
Stuttgart Media University
Nobelstrasse 10, 70569 Stuttgart, Germany
www.hdm-stuttgart.de/bi