Jacobi polynomials and harmonic weight enumerators of the first-order Reed--Muller codes and the extended Hamming codes
Tsuyoshi Miezaki, Akihiro Munemasa
TL;DR
The paper computes explicit Jacobi polynomials $J_{C,T}$ and $J_{C^ot,T}$ for the first-order Reed–Muller codes $RM(1,m)$ and their duals (extended Hamming codes $H_{2^m}$) and derives harmonic weight enumerators $w_{C,f}$ and $w_{C^ot,f}$ using Bachoc’s framework. By analyzing these polynomials—particularly through subspace restrictions and MacWilliams-type identities—it establishes precise conditions under which shells fail to form combinatorial $4$-designs. It provides two independent proofs of the nonexistence of $4$-designs in any shell, one via Jacobi polynomial differences and another via a harmonic function in $ ext{Harm}_4$ drawn from a $3$-$(8,4,1)$ design. Collectively, the results rule out $4$-designs in the shells of $RM(1,m)$ and $H_{2^m}$ and showcase the power of Jacobi polynomials and harmonic weight enumerators in design-theoretic analyses of classical codes.
Abstract
In the present paper, we give harmonic weight enumerators and Jacobi polynomials for the first-order Reed--Muller codes and the extended Hamming codes. As a corollary, we show the nonexistence of combinatorial $4$-designs in these codes.
