How to change a property attached to the whole graph

Question

Does anyone know how to change graph property "Norm". A command;

G = SetProperty[G, "GraphProperties" -> {"Norm" -> 1}]

doesn't work as I expected. Here is the graph constructor;

G = Graph[{Property[1, "Potential" -> 11],2,3,4},
          {Property[2 -> 1, "PreferenceIntensity" -> 5], 3 -> 1, 3 -> 2, 1 -> 4},
          EdgeWeight -> {5, 3, 4, 2},
          Properties -> {"GraphProperties" -> {"Norm" -> 5}},
          VertexLabels -> "Name", ImagePadding -> 10] ;

Thanks.

Answer 1

In[1]:= g = Graph[{1 \[DirectedEdge] 2, 2 \[DirectedEdge] 3, 3 \[DirectedEdge] 1}, 
    Properties -> {"GraphProperties" -> {"Norm" -> 1}}];
g2 = SetProperty[g, Properties -> {"GraphProperties" -> {"Norm" -> 5}}];
PropertyValue[#, "Norm"] & /@ {g, g2}


Out[1]= {1, 5}

Answer 2

This may work:

Graph[G, Properties -> {"GraphProperties" -> {"Norm" -> 1}}]

Generally you should avoid creating symbol names that start with a capital letter, so use g in the future.