- combinatorics (4),
- functional-analysis (1),
- graph-theory (2),
- group-theory (3),
- linear-algebra (1),
- number-theory (2),
- optimization (1),
- quantum-information (1),
- recreational-mathematics (4)
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Orbit counting lemma
A graph-theoretic proof of the orbit-counting theorem.
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Matrix recurrence for non-backtracking walks
A matrix recurrence for walks that avoid immediately retracing the last edge.
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Graham-Pollak determinant formula
A beautiful formula for the determinant of the distance matrix of a tree.