For more information about this meeting, contact Robert Vaughan.

Title: | On Improved asymptotic bounds for codes from global function fields |

Seminar: | Algebra and Number Theory Seminar |

Speaker: | Siman Yang, East China Normal University |

Abstract: |

For a prime power $q$, let $alpha_q$ be the standard function in the asymptotic theory of codes, that is, $alpha_q(delta)$ is the largest asymptotic information rate that can be achieved by a sequence of $q$-ary codes with a given asymptotic relative minimum distance $delta$. In recent years several authors improved the Tsfasman-Vlv{a}duc{t}-Zink bound by establishing various lower bounds on $alpha_q(delta)$. In this talk, we present a further improvement on the lower bound on $alpha_q(delta)$ by extending a construction by Niederreiter and "{O}zbudak.In particular, we show that the bound $1-delta-A(q)^{-1}+log_q(1+2/q^3)+log_q(1+(q-1)/q^6)$ can be achieved for certain values of $q$ and certain ranges of $delta$. |

### Room Reservation Information

Room Number: | MB106 |

Date: | 09 / 25 / 2008 |

Time: | 11:15am - 12:05pm |