Geometry of Polyhedra Course

Lesson 1 • Defining Polyhedra and Their Parts

Introduces the formal definition of a polyhedron and its structural components. Establishes vocabulary used throughout the entire course.

Lesson 2 • Polygonal Faces and Edge Relationships

Examines how polygonal faces meet along edges and at vertices. Connects face geometry to overall solid structure.

Lesson 3 • Basic Classification by Face Type

Organises polyhedra by the shapes and regularity of their faces. Prepares students for deeper taxonomies in later chapters.

Lesson 1 • Proof of Exactly Five Platonic Solids

Walks through the angle-deficit argument proving no sixth regular convex polyhedron exists. Reinforces logical proof-writing skills.

Lesson 2 • Metric Properties of Platonic Solids

Derives surface area, volume, and circumradius formulas for each Platonic solid. Applies algebraic manipulation to geometric measurement.

Lesson 3 • Symmetry Groups of Platonic Solids

Identifies rotation and reflection symmetries of each Platonic solid using group theory basics. Connects geometric symmetry to algebraic structure.

Lesson 4 • The Five Platonic Solids

Presents the tetrahedron, cube, octahedron, dodecahedron, and icosahedron with full geometric data. Students construct each solid and verify Euler's formula.

Lesson 1 • Expansion and Snub Operations

Covers expansion (cantellation) and snub operations that produce chiral Archimedean solids. Introduces chirality as a geometric property.

Lesson 2 • Complete Catalogue of Archimedean Solids

Surveys all 13 Archimedean solids with vertex configurations, face counts, and symmetry groups. Builds a reference framework for applied work.

Lesson 3 • Vertex Configuration Notation

Introduces the notation listing face types around each vertex, such as 3.4.3.4. Provides the primary tool for identifying semi-regular polyhedra.

Lesson 4 • Catalan Solids as Archimedean Duals

Derives each Catalan solid from its Archimedean dual and analyses face-transitivity. Closes the duality loop introduced in Chapter 3.

Lesson 1 • Dual Pairs Among Platonic Solids

Identifies the cube-octahedron, dodecahedron-icosahedron, and self-dual tetrahedron pairs. Reinforces Platonic solid knowledge through duality analysis.

Lesson 2 • Polar Reciprocity Construction

Constructs the geometric dual using a sphere of reciprocation centred at the centroid. Connects algebraic polarity to physical model building.

Lesson 3 • Combinatorial Duality

Defines the dual polyhedron by swapping vertex and face roles while preserving incidence. Establishes the combinatorial foundation before geometric constructions.

Lesson 1 • Antiprisms: Twisted Prism Variants

Introduces antiprisms formed by rotating one base and triangulating lateral faces. Compares antiprism properties with corresponding prisms.

Lesson 2 • General Formulas Across Families

Synthesises Euler data, symmetry orders, and metric formulas across prisms, antiprisms, and Johnson solids. Develops pattern-recognition skills for new solids.

Lesson 3 • Prisms: Structure and Properties

Defines n-gonal prisms, derives their Euler data, and computes surface area and volume. Establishes the first infinite family of polyhedra.

Lesson 1 • Stellation and Faceting Operations

Defines stellation as extending faces to new intersections and faceting as its dual operation. Applies both to Platonic solids to generate star forms.

Lesson 2 • Non-Convexity and Self-Intersection

Defines non-convex polyhedra and distinguishes self-intersecting from merely concave solids. Revises convexity assumptions from earlier chapters.

Lesson 3 • Non-Convex Archimedean and Uniform Solids

Surveys non-convex uniform polyhedra beyond the Kepler-Poinsot set, including hemipolyhedra. Completes the uniform polyhedron classification picture.

Lesson 4 • Density and Winding Numbers

Introduces face density and winding number to measure how many times a star solid wraps around its centre. Extends metric analysis to non-convex cases.

Lesson 1 • Counting and Enumeration Problems

Uses Burnside's lemma and Polya enumeration to count distinct polyhedra under symmetry. Applies group actions to combinatorial counting.

Lesson 2 • Polyhedral Graphs and Planarity

Represents polyhedra as planar graphs and applies Steinitz's theorem characterising valid polyhedral graphs. Connects topology to combinatorics.

Lesson 3 • Colourings and Map Problems

Applies graph colouring theory to polyhedral maps, including the four-colour theorem context. Develops combinatorial problem-solving on polyhedral surfaces.

Lesson 4 • Hamiltonian and Eulerian Paths

Investigates Hamiltonian cycles and Eulerian paths on polyhedral graphs. Applies classical graph theory results to specific polyhedra.

Lesson 1 • Polyhedra in Linear Programming

Models feasible regions of linear programmes as convex polyhedra and analyses vertices as optimal solutions. Connects geometric intuition to optimisation theory.

Lesson 2 • Polyhedra in Crystallography

Applies polyhedral symmetry groups to crystal lattice classification and unit cell geometry. Connects mathematical symmetry to physical crystal structures.

Lesson 3 • Higher-Dimensional Polytopes

Extends polyhedron concepts to 4D polytopes such as the 24-cell and 120-cell. Generalises Euler's formula to the Euler-Poincaré formula.

Lesson 4 • Computational Polyhedron Problems

Solves algorithmic problems including convex hull computation and polyhedral mesh generation. Bridges theoretical knowledge to computational geometry practice.