GRAPH GRAMMAR OPERATION ‘BISECT AN EDGE’	GRAPH GRAMMAR OPERATION ‘ADD NODE TO A NODE’
Applicable to: any edge of the graph	Applicable to: any node of the graph
Update of the graph structure: for a given edge {A,B}, connecting nodes A and B, remove {A,B} from the graph, add a new node C, and introduce two new edges {A,C} and {C,B}.	Update of the graph structure: for a given node A, add a new node C, and introduce a new edge {A,C}
Update of the elasticity matrix: the elasticity of edges {A,C} and {C,B} equals elasticity of {A,B}.	Update of the elasticity matrix:   if A is a leaf node (not a star center) then   the elasticity of the edge {A,C} equals to the edge connecting A and its neighbor, the elasticity of the new star with the center in A equals to the elasticity of the star centered in the neighbor of A. If the graph contains only one edge then a predefined values is assigned.   else   the elasticity of the edge {A,C} is the mean elasticity of all edges in the star with the center in A, the elasticity of a star with the center in A does not change.
Update of the graph injection map: C is placed in the mean position between the positions of A and B.	Update of the graph injection map:   if A is a leaf node (not a star center) then   C is placed at the same distance and the same direction as the edge connecting A and its neighbor,   else   C is placed in the mean point of all data points for which A is the closest node