gml:AbstractTopoPrimitive 

gml:AbstractTopoPrimitive acts as the base type for all topological primitives. Topology primitives are the atomic (smallest possible) units of a topology complex. 
Each topology primitive may contain references to other topology primitives of codimension 2 or more (gml:isolated). Conversely, nodes may have faces as containers and nodes and edges may have solids as containers (gml:container).

Element Information

Model

gml:metaDataProperty* , gml:description{0,1} , gml:descriptionReference{0,1} , gml:identifier{0,1} , gml:name*
Children: gml:description, gml:descriptionReference, gml:identifier, gml:metaDataProperty, gml:name

Attributes

QName Type Fixed Default Use Inheritable Annotation
gml:id ID required 
The attribute gml:id supports provision of a handle for the XML element representing a GML Object. Its use is mandatory for all GML objects. It is of XML type ID, so is constrained to be unique in the XML document within which it occurs.

Used By

Complex Types gml:TopoPrimitiveArrayAssociationType, gml:TopoPrimitiveMemberType

Source 

<element name="AbstractTopoPrimitive" type="gml:AbstractTopoPrimitiveType" abstract="true" substitutionGroup="gml:AbstractTopology">
  <annotation>
    <documentation>gml:AbstractTopoPrimitive acts as the base type for all topological primitives. Topology primitives are the atomic (smallest possible) units of a topology complex. Each topology primitive may contain references to other topology primitives of codimension 2 or more (gml:isolated). Conversely, nodes may have faces as containers and nodes and edges may have solids as containers (gml:container).</documentation>
  </annotation>
</element>

Sample