# David Toth

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bio website www1.maths.leeds.ac.uk/~mmdt location age member for 2 years, 6 months seen 17 hours ago profile views 154

2010 - 2014, Imperial College London, MEng Computing (Artificial Intelligence)

2014 - 2017, University of Leeds, a PhD candidate in Computability Theory

# 62 Questions

 8 Can we expand numbers on the left to produce irrational numbers? 7 What is $\aleph_0$ powered to $\aleph_0$? 6 If $S_n$ is a symmetric group, what is the name for $n$? 5 Show a subspace formed by a Klein bottle is homotopy-equivalent to $S^1 \vee S^1 \vee S^2$ 4 $dcl(A)=\{x \in M : x$ definable from $A \}$, Show $dcl(dcl(A)=A$

# 846 Reputation

 +5 $\exists G \in L'. G \iff \mathtt{True}(gn(\neg G))$ in the language $L'$ with Godel numbering $gn$ and $\mathtt{True}$ predicate? +5 What is effectively continuous? +5 Why is an empty set not a terminal object in categories $\mathsf{Top}$ and $\mathsf{Sets}$? +5 $dcl(A)=\{x \in M : x$ definable from $A \}$, Show $dcl(dcl(A)=A$

# 9 Answers

 4 $dcl(A)=\{x \in M : x$ definable from $A \}$, Show $dcl(dcl(A)=A$ 2 $\pi_1(X)$ finite, show $f:X \to S^1$ is nullhomotopic 1 Question about null-homotopic function 0 What is effectively continuous? 0 Is the given Language decidable or recognizable?

# 59 Tags

 1 algebraic-topology × 15 0 group-theory × 7 1 homotopy-theory × 2 0 computability × 5 0 definition × 11 0 notation × 5 0 model-theory × 8 0 linear-algebra × 4 0 manifolds × 7 0 category-theory × 4

# 20 Accounts

 Mathematics 846 rep 313 Academia 482 rep 315 Computer Science 323 rep 18 English Language & Usage 240 rep 28 Super User 135 rep 7

# 15 Badges

 Popular Question Yearling × 2 Tumbleweed Critic Autobiographer Self-Learner Curious Teacher Inquisitive Editor

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# 248 Votes Cast

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247 up 96 question 3
1 down 152 answer