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 $L(D)= \{ s: \exists x \in D_{s}  D_{s1} \ \hbox{and} \ x \not\in D\}$.
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 IMSJSPS 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.
