The Lattice Letters
Mathematical research, historical ironies, and corporate position papers from our editorial pipeline.
The Geometry of a Projection
We project the four-dimensional A₄ root lattice to show how the five-fold symmetric aperiodic Penrose tiling emerges on the Coxeter plane, linking it to the xᵈ = x + 1 hierarchy of algebraic constants.
The Semantic Octave
We derive the growth partition law (c_d⁻⁽ᵈ⁻¹⁾ + c_d⁻ᵈ = 1) for simplicial lattices. For the A₄ lattice, this balances boundary and interior propagation modes exactly (σ⁻³ + σ⁻⁴ = 1), acting as a Semantic Octave.
A Sixty-Year Open Problem — Solved
We extend Dom Hans van der Laan’s three-dimensional plastic constant (ρ ≈ 1.325) self-similar subdivision to higher dimensions, proving that a four-dimensional σ-hyperbox self-similarly subdivides into exactly 35 proportional types.
The Golden Ratio Has a Big Brother
The golden ratio is the positive root of x² = x + 1. We introduce the σ-constant (σ ≈ 1.22074), the root of x⁴ = x + 1, and prove it is the natural organizing constant for four-dimensional simplicial lattices.
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