Sunday, 8 March 2015
10:00 - 10:45 Shota Murakami (Tohoku University)
Title : TBA

Abstract

TBA
11:00 - 11:45 Takeshi Yamazaki (Tohoku University)
Title : TBA

Abstract

TBA
Lunch
14:00 - 14:30 Shohei Okisaka (Tohoku University)
Title : Partial order on Lindstrom extensions

Abstract

TBA
14:45 - 15:30 Wu Guohua (Nanyang Univ. of Technology)
Title : Nonexistence of Minimal Pairs in L[d]

Abstract

For a d.c.e. set $D$ with a d.c.e. approximation $\{D_s\}_{s\in\omega}$, the Lachlan set of $D$ is defined as $L(D)= \{ s: \exists x \in D_{s} - D_{s-1} \ \hbox{and} \ x \not\in D\}$. For a d.c.e. degree ${\mathbf d}$, $L[{\bf d}]$ is defined as the class of c.e. degrees of those Lachlan sets of d.c.e. sets in ${\bf d}$. We prove that for any proper d.c.e. degree ${\bf d}$, no two elements in $L[{\bf d}]$ can form a minimal pair. This result gives another solution to Ishmukhametov's problem, which asks whether for any proper d.c.e. degree ${\bf d}$, $L[{\bf d}]$ always has a minimal element. A negative answer to this question was first given by Fang, Wu and Yamaleev in 2013.
Coffee Break
16:00 - 16:30 Wenjuan Li (Tohoku University)
Title : TBA

Abstract

TBA
16:45 - 17:30 Yang Yue (National Univ. of Singapore)
Title : A normal form theorem of computation on reals

Abstract

This talk is a continuation of what I presented in the IMS-JSPS workshop at National University of Singapore in September 2014. I will define two formalizations of computations on real numbers and sketch a proof of their equivalence. From the proof, one can derive a Kleene style Normal Form Theorem. This is a joint work with Keng Meng Ng from NTU, Singapore and Nazanin Tavana from IPM, Iran.