Assertion: curve's point | /r/HasProperty | vertex
Facets:
value: for a circle
type: TRANSITIVE-OBJECT
Source sentences:
text: For a circle, which has constant curvature, every point is a vertex.
text: The point where the parabola intersects its axis of symmetry is called the "vertex" and is the point where the parabola is most sharply curved.
text: For example, if two circular arcs meet at a sharp point (a vertex) then there is no uniquely defined tangent at the vertex because the limit of the progression of secant lines depends on the direction in which "point B" approaches the vertex.