Magritte - representing multiple relationships between two classes

> I am just about to dip my toe into trying out Magritte to implement a UML
> model and would like to clarify how bidirection relationships work.
>
> Section 2.6.1 of [1] says... "A relationship is always defined from the
> described object to the referenced object.
> To describe a two-way relationship the developer has to define a relationship
> description at both ends of the association."
> I haven't seen a specific Magritte example of that, but I assume it is
> similar to the Phosyden example [2]
>
>> personEntity hasOne: #Pet as: #myPet.
>> petEntity hasOne: #Person as: #owner.
>
>
> That makes sense where there is only a single relation between two classes.
> However where there are two relations between two classes as shown in
> attached image, how are relations (1a,1b) paired together and (2a,2b) pair
> together. Or would this pairing generally be of no consequence?
>
> I would naively assume these four definitions...
> 1a. topologicalNodeEntity hasOne: #TopologicalIsland as: #topologicalIsland.
> 1b. topologicalIslandEntity hasMany: #TopologicalNode as: #topologicalNodes.
> 2a. topologicalNodeEntity hasOne: #TopologicalIsland as:
> #angleRefTopologicalIsland.
> 2b. topologicalIslandEntity hasOne: #TopologicalNode as:
> #angleRefTopologicalNode.
>
> cheers, Ben
>
> [1] http://www.iam.unibe.ch/~scg/Archive/Diploma/Reng06a.pdf
> [2]
> http://dbxtalk.smallworks.com.ar/pier/Documentation/mission-4_-about-relations
>
>
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