15 papers
Uniform Sampling of Linear Codes with Prescribed Hull Dimension
Keita Ishizuka
We give exactly uniform samplers for linear codes with prescribed hull dimension, for the Euclidean, Hermitian, and symplectic inner products and over finite fields of every charac…
Classification of binary, ternary and quaternary Hermitian LCD codes
Keita Ishizuka
We extend the complete classifications of linear complementary dual (LCD) codes from length 15 to length 19 in the binary case, from length 10 to length 15 in the ternary case and…
Enumeration and Monotonicity of Linear Codes with Prescribed Hull Dimensions
Stefka Bouyuklieva, Keita Ishizuka, Iliya Bouyukliev +1
The hull of a linear code is the intersection of the code with its dual and depends on the choice of inner product. We study how the numbers of linear codes with prescribed Euclide…
The Closure of LCD-to-GI Reductions via Generalized Inner Products
Keita Ishizuka
The Permutation Equivalence Problem (PEP) for linear complementary dual (LCD) codes reduces to Graph Isomorphism (GI) through the orthogonal projector onto the code, but this requi…
Caps and LCD Codes with Large Dimensions
Keita Ishizuka, Yuhi Kamio
We establish a connection between linear complementary dual (LCD) codes and caps in projective space. Using this framework and the structure theory of maximal binary caps, we deriv…
Almost All Vectorial Functions Have Trivial Extended-Affine Stabilizers
Keita Ishizuka
We prove that asymptotically almost all vectorial functions over finite fields have trivial extended-affine stabilizers. As a consequence, the number of EA-equivalence classes is a…
Constructions of self-orthogonal and LCD subspace codes
Dean Crnković, Keita Ishizuka, Hadi Kharaghani +2
Recently, the notions of self-orthogonal subspace codes and LCD subspace codes were introduced, and LCD subspace codes obtained from mutually unbiased weighing matrices were studie…
Binary LCD Codes and Their Graph Representations
Keita Ishizuka
We give a complete characterization of simple graphs whose adjacency matrices generate binary linear complementary dual (LCD) codes. In particular, we completely characterize a dis…
Ternary extremal four-negacirculant self-dual codes
Masaaki Harada, Keita Ishizuka, Hadi Kharaghani
In this note, we give basic properties of ternary four-negacirculant self-dual codes. By exhaustive computer search based on the properties, we complete a classification of ternary…
Hadamard matrices of order formed by codewords in some ternary self-dual codes
Masaaki Harada, Keita Ishizuka
In this note, we study the existence of Hadamard matrices of order formed by codewords of weight in some ternary near-extremal self-dual codes of length .
Construction of quaternary Hermitian LCD codes
Keita Ishizuka
We introduce a general construction of many Hermitian LCD codes from a given Hermitian LCD code. Furthermore, we present some results on punctured codes and short…
Construction for both self-dual codes and LCD codes
Keita Ishizuka, Ken Saito
From a given code , we give a method for constructing many codes such that the hull dimensions of and are identical. This method can be applied t…
On the existence of quaternary Hermitian LCD codes with Hermitian dual distance
Keita Ishizuka, Ken Saito
For and a positive integer , we show that if there exists no quaternary Hermitian linear complementary dual code with and Hermitian dual distan…
Classification of optimal quaternary Hermitian LCD codes of dimension
Keita Ishizuka
Hermitian linear complementary dual codes are linear codes whose intersection with their Hermitian dual code is trivial. The largest minimum weight among quaternary Hermitian linea…
Developing a Multi-Platform Speech Recording System Toward Open Service of Building Large-Scale Speech Corpora
Keita Ishizuka, Takashi Nose
This paper briefly reports our ongoing attempt at the development of a multi-platform browser-based speech recording system. We designed the system toward a service of providing op…