“30” “30”](mstkla.md#parent-child) “30” “30”](mstkla.md) “30” “30”](prelim.md) 

Parent-Child Node (Vertex) Issues 

All the operators are designed to work consistently with parent and child nodes(if they exist) consistently. Operators exist for getting the parent of a vertex, edge and face. The parent edge/face of a  edge/face is constructed from the parents of its component vertices. Operators also exist for obtaining the child vertices/edges/faces of vertices/edges/faces.

The upward and downward adjacency information is designed to be returned in a consistent manner as described below. If upward adjacency information is requested for a child entity then only those higher order entities connected to the child will be returned. On the other hand, if it is requested for a parent, upward adjacency information from all its children will be consolidated and returned. For example, if regions of a child vertex (node) are requested, then only the regions classified in that model region will  be returned. On the other hand if one wants all the regions in all model regions connected to the node, one should get the parent of the vertex and ask for the regions connected to the parent vertex.  The behavior of downward adjacency information queries is determined by the type of entity and how it is constructed. Asking for the nodes of a vertex will return only the child nodes if any of the nodes are on  an interface. Parent faces and edges on an interface will return parent nodes and child faces and edges on an interface will return child nodes. Lastly, if the entity is not on an interface, it is its own parent or its own child. “30” “30”](mstkla.md#parent-child) “30” “30”](mstkla.md) “30” “30”](prelim.md)