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Vertex (curve)

In the geometry of plane curves, a vertex is a point of where the first derivative of curvature is zero.

Version
v1 · 2026-09-28 · History
Domain-specific #
12786
Domain group
Formal Sciences
Origin domain
Mathematics
Subdomains
Differential Geometry, Plane Curves → Mathematics

Core Idea

Vertex (curve) is treated here as the recurring mathematicslogicstatistics identity summarized by this source-grounded definition: In the geometry of plane curves, a vertex is a point of where the first derivative of curvature is zero. In the geometry of plane curves, a vertex is a point of where the first derivative of curvature is zero. This is typically a local maximum or minimum of curvature, and some authors define a vertex to be more specifically a local extremum of curvature.

Scope of Application

  • Examples. A hyperbola has two vertices, one on each branch; they are the closest of any two points lying on opposite branches of the hyperbola, and they lie on the principal axis.

  • Examples. On a parabola, the sole vertex lies on the axis of symmetry and in a quadratic of the form.

  • Examples. On an ellipse, two of the four vertices lie on the major axis and two lie on the minor axis.

  • Examples. For a circle, which has constant curvature, every point is a vertex.

  • Cusps and osculation. Vertices are points where the curve has 4-point contact with the osculating circle at that point.

Clarity

A clear use of Vertex (curve) names the carrier, the operative relation, and the conditions under which the source treats the identity as present. The minimal definition is In the geometry of plane curves, a vertex is a point of where the first derivative of curvature is zero.

Manages Complexity

Vertex (curve) compresses multiple mathematicslogicstatistics details into a stable diagnostic relation. The source shows both the central mechanism—a hyperbola has two vertices, one on each branch; they are the closest of any two points lying on opposite branches of the hyperbola, and they lie on the principal axis.—and the practical consequence—vertices are points where the curve has 4-point contact with the osculating circle at that point.

Abstract Reasoning

  1. Type the carrier. Identify the mathematicslogicstatistics entities to which the claim applies.
  2. State the relation. Use the source-grounded identity: In the geometry of plane curves, a vertex is a point of where the first derivative of curvature is zero.
  3. Check operation and conditions. On a parabola, the sole vertex lies on the axis of symmetry and in a quadratic of the form.
  4. Demand recognition evidence.

Knowledge Transfer

Within the home domain. Knowledge about Vertex (curve) transfers literally when a new case preserves the same carrier type, relation, and recognition test. A hyperbola has two vertices, one on each branch; they are the closest of any two points lying on opposite branches of the hyperbola, and they lie on the principal axis. On a parabola, the sole vertex lies on the axis of symmetry and in a quadratic of the form. Beyond the home domain. No canonical parent is asserted for Vertex (curve).

Relationships to Other Abstractions

Local relationship map for Vertex (curve)Parents appear above the current abstraction, mutual partners to the right, and children below. Node labels state whether each abstraction is prime or domain-specific; colors identify relation types.Vertex (curve)DOMAINDomain-specific abstraction: Curve — presupposesCurveDOMAIN

Current abstraction Vertex (curve) Domain-specific

Parents (1) — more general patterns this builds on

  • Vertex (curve) presupposes Curve Domain-specific

    A curve vertex is defined by a curvature-extremum condition on an ambient plane curve.

Hierarchy paths (2) — routes to 2 parentless roots

Neighborhood in Abstraction Space

Vertex (curve) sits in a moderately populated region (50th percentile for distinctiveness): it has near-neighbors but no dense thicket of look-alikes.

Family — Geometric Figures & Constructions (32 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-10-08