Here is a list of projective codes.

Code | Description |
---|---|

Cycle LDPC code | An LDPC code whose parity-check matrix forms the incidence matrix of a graph, i.e., has weight-two columns. |

Cycle code | A code whose parity-check matrix forms the incidence matrix of a graph. This code's properties are derived from the size two chain complex associated with the graph. |

Denniston code | Projective code that is part of a family of \([2^{a+i}+2^i-2^a,3,2^{a+i}-2^a]_{GF(2^a)}\) codes for \(i < a\) constructed using Denniston arcs. |

Glynn code | The unique trace-Hermitian self-dual \([10,5,6]_9\) code, constructed using a 10-arc in \(PG(4,9)\) that is not a rational curve. |

Hexacode | The \([6,3,4]_4\) self-dual MDS code that has connections to projective geometry, lattices [1], and conformal field theory [2]. Puncturing the code yields the perfect \([5,3,3]_4\) quaternary Hamming code known as the shortened hexacode or shorter hexacode [3]. Both codes are sometimes refereed to as Golay codes over \(GF(4)\). |

Hill projective-cap code | Member of a projective code family that contains of \(q\)-ary sharp configurations and that is constructed using projective caps. |

Hirschfeld code | A projective geometry code that is an example of an MDS code that is not an RS code; see [4; Exam. 7.6] for the description. |

Hoffman-Singleton cycle code | A \([50,21,12]\) cycle code whose parity-check matrix is the incidence matrix of the Hoffman-Singleton graph [5]. Its dual is a \([50,29,8]\) code [6; Table II]. |

Hyperoval code | A projective code constructed using hyperovals in projective space. |

Incidence-matrix projective code | Code whose generator matrix is the incidence matrix of points and hyperplanes in a projective space. Has been generalized to incidence matrices of other structures [7,8][9; Sec. 14.4]. Columns of a code's parity-check matrix can similarly correspond to an incidence matrix. |

Margulis LDPC code | Member of a class of LDPC codes deterministically constructed using a class of regular graphs with no short cycles. Related explicit LDPC constructions [10] utilize Ramanujan graphs [11,12]. |

Ovoid code | Member of a \([q^2+1,4,q^2-q]_q\) projective code family that is universally optimal and that is constructed using ovoids in projective space. See [13; pg. 107][14; pg. 192] for further details. |

Petersen cycle code | A \([15,6,5]\) cycle code whose parity-check matrix is the incidence matrix of the Petersen graph. The Petersen graph can be thought of as a dodecahedron with antipodes identified [15; Appx. A.2.1]. |

Projective geometry code | Linear \(q\)-ary \([n,k,d]\) code such that columns of its generator matrix \(G\) does not contain any repeated columns or the zero column. That way, each column corresponds to a distinct point in the projective space \(PG(k-1,q)\) arising from a \(k\)-dimensional vector space over \(GF(q)\). If the columns are linearly independent, then the codewords are collectively called an information set. Columns of a code's parity-check matrix can similarly correspond to points in projective space. This formulation yields connections to projective geometry, which can be applied to determine code properties. |

Projective two-weight code | A projective code whose codewords all have one of two possible nonzero Hamming weights. |

Tetracode | The \([4,2,3]_3\) self-dual MDS code that has connections to lattices [1]. |

\([2^m-1,m,2^{m-1}]\) simplex code | A member of the code family that is dual to the \([2^m,2^m-m-1,3]\) Hamming family. The columns of its generator matrix are in one-to-one correspondence with the elements of the projective space \(PG(m-1,2)\), with each column being a chosen representative of the corresponding element. The codewords form a \((2^m,2^m+1)\) simplex spherical code under the antipodal mapping. |

\([56,6,36]_3\) Hill-cap code | Projective two-weight ternary code based on the Games graph [17][16; Table 19.1] and Hill's 56-cap [18]. Its automorphism group contains \(PSL_3(4)\) [19]. |

\([7,3,4]\) simplex code | Second-smallest member of the simplex code family. The columns of its generator matrix are in one-to-one correspondence with the elements of the projective space \(PG(2,2)\), with each column being a chosen representative of the corresponding element. The codewords form a \((8,9)\) simplex spherical code under the antipodal mapping. |

\([78,6,56]_4\) Hill-cap code | Projective two-weight quaternary code based on a cap that corresponds to a strongly regular graph [17; Table 7.1]. |

\(q\)-ary simplex code | An \([n,m,q^{m-1}]_q\) projective code with \(n=\frac{q^m-1}{q-1}\), denoted as \(S(q,m)\). The columns of the generator matrix are in one-to-one correspondence with the elements of the projective space \(PG(m-1,q)\), with each column being a chosen representative of the corresponding element. |

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