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二元关系的枚举

The Enumeration of Binary Relations

Mamadou Sadialiou Bah

arXiv 2607.17153首次发表:更新:

AI 中文总结

研究有限集间二元关系等相关对象的组合类型枚举问题,核心方法是利用柯西 - 弗罗贝尼乌斯 - 伯恩赛德引理,主要贡献是确定了各类计数的生成函数并验证相关公式,还提供了从基础展开的工具便于学习。

AI 中文摘要

有限集\(N\)与\(X\)之间的二元关系、子集族以及从\(P(N)\)到\(P(X)\)的格同态是同一对象的三个方面。本专著合并并大幅扩展了作者1997年的ICTP预印本IC/97/180及2026年的一篇附注,通过柯西 - 弗罗贝尼乌斯 - 伯恩赛德引理枚举了每种组合类型(任意、单射、满射、双边),包括原始的以及在对称群\(S_N\)、\(S_X\)和\(S_N\times S_X\)作用下的情况。接着确定了所有计数的生成函数,揭示了\(e^{z + w + zw}\)、贝尔数、欧拉划分乘积以及表格中最难的双边列的拟多项式性。所有必备工具都从第一原理展开,经代数和组合学入门课程后即可读懂。书中包含了对1997年预印本定理B的修正记录,所有公式均经符号计算和暴力枚举验证。

英文摘要

Binary relations between finite sets N and X, families of subsets, and lattice homomorphisms from P(N) to P(X) are three faces of the same object. This self-contained monograph, merging and substantially expanding the author's ICTP preprint IC/97/180 (1997) and a 2026 companion note, enumerates every combinatorial type (arbitrary, injective, surjective, on either side), both raw and up to the actions of the symmetric groups S_N, S_X, and S_N x S_X, via the Cauchy-Frobenius-Burnside lemma. The generating functions of all counts are then determined, revealing e^{z+w+zw}, Bell numbers, Euler's partition product, and the quasi-polynomiality of the hardest, two-sided column of the table. All prerequisite tools -- elementary counting, group actions, Stirling and Bell numbers, formal power series, and Mobius inversion on the Boolean lattice -- are developed from first principles, making the book accessible after a first course in algebra and combinatorics. A documented correction to Theorem B of the 1997 preprint is included; all formulas have been verified by symbolic computation and brute-force enumeration.

Comments64 pages. Self-contained monograph merging and expanding ICTP preprint IC/97/180 (1997) and a 2026 companion note. All formulas verified by symbolic computation and brute-force enumeration

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