Marc van Leeuwen

Poitiers, France

http://www-math.univ-poitiers.fr/~maavl/

professor of mathematics at the Université de Poitiers (France)

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Is there any concrete relation between Gödel's incompleteness theorem, the halting problem and universal Turing machines?

computability logic halting-problem incompleteness asked Mar 15, 2012 at 16:43

cs.stackexchange.com

72 votes

Determinant of a rank $1$ update of a scalar matrix, or characteristic polynomial of a rank $1$ matrix

linear-algebra matrices determinant characteristic-polynomial faq asked Aug 21, 2014 at 10:08

math.stackexchange.com

48 votes

Can commuting matrices $X,Y$ always be written as polynomials of some matrix $A$?

linear-algebra abstract-algebra matrices asked Mar 10, 2013 at 9:42

math.stackexchange.com

47 votes

In C++11, does `i += ++i + 1` exhibit undefined behavior?

c++ c++11 language-lawyer undefined-behavior asked Jun 12, 2014 at 21:17

stackoverflow.com

34 votes

How to explicitly call a namespace-qualified destructor?

c++ g++ standards clang++ asked Jul 6, 2014 at 8:11

stackoverflow.com

24 votes

Does an expression with undefined behaviour that is never actually executed make a program erroneous?

c++ language-lawyer undefined-behavior asked Jun 12, 2014 at 14:15

stackoverflow.com

23 votes

Can a group have a subset that is stable under all automorphisms, but not under inverse?

group-theory asked Jun 14, 2014 at 16:25

math.stackexchange.com

13 votes

Nice proof that expected number of $k$-cycles in a permutation of $n$ is $\frac1k$ whenever $0<k\leq n$

probability combinatorics permutations asked Jul 6, 2022 at 7:02

math.stackexchange.com

7 votes

How to use SFINAE to restrict overload to input iterators

c++ templates c++11 asked Sep 4, 2014 at 15:06

stackoverflow.com

6 votes

Size bound on regular expression describing language of an $n$-state deterministic automaton

computer-science computability formal-languages asked Feb 4, 2012 at 14:06

math.stackexchange.com

Top Answers

150

How to learn from proofs?

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Does C++ compiler remove/optimize useless parentheses?

softwareengineering.stackexchange.com

Is "women men girls love meet die" a valid sentence?

english.stackexchange.com

Why doesn't induction extend to infinity? (re: Fourier series)

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Are $10\times 10$ matrices spanned by powers of a single matrix?

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How do I pass a unique_ptr argument to a constructor or a function?

stackoverflow.com

Are "if" and "iff" interchangeable in definitions?

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Is $\mathbb{Z}[x]$ a principal ideal domain?

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Two dice thrown, one comes up 6

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How can I evaluate $\sum_{n=0}^\infty(n+1)x^n$?

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Sylvester rank inequality: $\operatorname{rank} A + \operatorname{rank}B \leq \operatorname{rank} AB + n$

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Is there a commutative operation for which the inverse of the operation is also commutative?

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What is the difference between being unique, unique up to isomorphism and unique up to unique isomorphism?

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deformation retract of $GL_n^{+}(\mathbb{R})$

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Sum and Divisibility Puzzle

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What is the norm of a complex number?

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100 blue-eyed islanders puzzle: 3 questions

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nonlocal keyword in Python 2.x

stackoverflow.com

Matrix is conjugate to its own transpose

math.stackexchange.com

What's an intuitive way to think about the determinant?

math.stackexchange.com

why do we use 'non-increasing' instead of decreasing?

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$m!n! < (m+n)!$ Proof?

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My son's Sum of Some is beautiful! But what is the proof or explanation?

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Example of a finitely generated module with submodules that are not finitely generated

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Is adjoint of singular matrix singular? What would be its rank?

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Determinant of a rank $1$ update of a scalar matrix, or characteristic polynomial of a rank $1$ matrix

math.stackexchange.com

When are minimal and characteristic polynomials the same?

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Which symbol should be used for an empty set?

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Show that ideal is a subring

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How does a branch cut define a branch?

math.stackexchange.com