-println("Spin-5/2 (Mn²⁺): ", spin_eigenvalues(5/2)) # [-5/2, -3/2, -1/2, 1/2, 3/2, 5/2]</code></pre><p><strong>Key insight</strong>: For <strong>any</strong> dimension <span>$n = 2j+1$</span>, if matrix has SU(2) symmetry, eigenvalues are immediately known without computation!</p><hr/><h2 id="Summary"><a class="docs-heading-anchor" href="#Summary">Summary</a><a id="Summary-1"></a><a class="docs-heading-anchor-permalink" href="#Summary" title="Permalink"></a></h2><p>These examples demonstrate that <strong>group theory transforms impossible problems into tractable ones</strong>:</p><ol><li><strong>Pentagon (5×5)</strong>: Degree-5 polynomial → Two quadratics (via <span>$D_5$</span> symmetry)</li><li><strong>Petersen (10×10)</strong>: Degree-10 polynomial → Direct formula (3 values only!)</li><li><strong>Hypercube (<span>$2^n$</span> vertices)</strong>: Exponentially large → Binomial coefficients</li><li><strong>BCCB</strong>: Million-dimensional image → FFT in milliseconds</li><li><strong>Benzene</strong>: 6×6 Hückel → Cosine formula (circulant structure)</li><li><strong>Solvable quintics</strong>: Degree-5 → Nested radicals (when Galois group is solvable)</li><li><strong>Spin systems</strong>: Arbitrary size → Integer eigenvalues (SU(2) representation)</li></ol><p>The common thread: <strong>Symmetry constrains eigenvalue structure</strong>, often reducing intractable problems to closed-form solutions or efficient algorithms.</p></article><nav class="docs-footer"><a class="docs-footer-prevpage" href="../pattern_library/">« Pattern Library</a><a class="docs-footer-nextpage" href="../implementation/">Implementation Details »</a><div class="flexbox-break"></div><p class="footer-message">Powered by <a href="https://github.com/JuliaDocs/Documenter.jl">Documenter.jl</a> and the <a href="https://julialang.org/">Julia Programming Language</a>.</p></nav></div><div class="modal" id="documenter-settings"><div class="modal-background"></div><div class="modal-card"><header class="modal-card-head"><p class="modal-card-title">Settings</p><button class="delete"></button></header><section class="modal-card-body"><p><label class="label">Theme</label><div class="select"><select id="documenter-themepicker"><option value="auto">Automatic (OS)</option><option value="documenter-light">documenter-light</option><option value="documenter-dark">documenter-dark</option><option value="catppuccin-latte">catppuccin-latte</option><option value="catppuccin-frappe">catppuccin-frappe</option><option value="catppuccin-macchiato">catppuccin-macchiato</option><option value="catppuccin-mocha">catppuccin-mocha</option></select></div></p><hr/><p>This document was generated with <a href="https://github.com/JuliaDocs/Documenter.jl">Documenter.jl</a> version 1.16.1 on <span class="colophon-date" title="Friday 12 December 2025 22:51">Friday 12 December 2025</span>. Using Julia version 1.12.2.</p></section><footer class="modal-card-foot"></footer></div></div></div></body></html>
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