7.46: Example for injective, label-preserving graph morphisms

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felicis
BASIC-Programmierer
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7.46: Example for injective, label-preserving graph morphisms

Beitrag von felicis » 7. Jul 2016 16:19

Hi,
does someone know a graph morphism \(r=(\operatorname{\mathit{v-f}}, \operatorname{\mathit{e-f}})\) for the De-Jure-Rule "x creates \(\alpha\) for new object y"?
I don't get how we could create the y subject when we only have \(\operatorname{\mathit{v-f}}: V_L \rightarrow V_R\), i.e. we can't tell the function to create anything, which didn't exist before!!
:(
felicis

Boddlnagg
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Re: 7.46: Example for injective, label-preserving graph morphisms

Beitrag von Boddlnagg » 9. Jul 2016 15:02

This is how I understand it:

The graph morphism \(r\) can't express any newly created objects, that's true. But the rewrite rule \(rr=(L,R,r)\) also contains \(L\) (which consists of x in that case) and \(R\) (which contains x and y). The graph morphism part of the rule only specifies how existing nodes should be changed. Newly created nodes are specified by whatever is in \(R\) and not in \(L\). The m* on Slide 48 (Module 7) would express this, since it captures the relationship between \(R\) and \(PG'\), although the details weren't specified in the lecture.

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