Sunday, 8 March 2015
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10:00 - 10:45
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Shota Murakami (Tohoku University)
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Title : TBA
Abstract
TBA
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11:00 - 11:45
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Takeshi Yamazaki (Tohoku University)
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Title : TBA
Abstract
TBA
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Lunch
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14:00 - 14:30
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Shohei Okisaka (Tohoku University)
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Title : Partial order on Lindstrom extensions
Abstract
TBA
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14:45 - 15:30
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Wu Guohua (Nanyang Univ. of Technology)
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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.
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Coffee Break
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16:00 - 16:30
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Wenjuan Li (Tohoku University)
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Title : TBA
Abstract
TBA
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16:45 - 17:30
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Yang Yue (National Univ. of Singapore)
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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.
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