User Peter LeFanu Lumsdaine - Mathematics Stack Exchange

2 votes

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Find the number of pairs of two consecutive zeros

answered May 1 at 19:26

2 votes

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Define the sum of transfinite ordinal sequences according to finite ordinal sum.

answered May 9 at 11:25

2 votes

On the reiteration (or repetition) rule in natural deduction: is the rule "obvious" or does it need a proof?

answered Feb 25, 2020 at 19:56

2 votes

Replacing a family of epimorphisms by epimorphisms with the same domain by forming pullbacks in an abelian category

answered Apr 9, 2022 at 12:50

2 votes

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How do I show P(Z = z) if Z = X+Y, both random discrete variables.

answered Apr 19, 2022 at 13:09

1 vote

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Fundamental group of wedge of two projective planes

answered Apr 10, 2022 at 23:12

1 vote

How to understand intuitively why "$\exists !x \exists !y$" is not equivalent to "$\exists !y \exists !x$"?

answered Apr 18, 2022 at 7:33

1 vote

How to show that $\{(x, y) \in \mathbb{R}^2\mid\cos(x^2) + x^3 - 4 7y > e^x - y^2\}$ is open or closed?

answered May 25, 2020 at 17:58

1 vote

How to show this ring homomorphism is surjective?

answered Jun 12, 2021 at 23:57

1 vote

prove two different forms of the same uniqueness theorem are logically equivalent

answered Dec 6, 2013 at 22:32

1 vote

Accepted

Combining products of like terms in a division

answered Dec 6, 2013 at 22:56

1 vote

XOR of Three Integers

answered Jan 3, 2014 at 1:09

1 vote

A set contains $0$, $1$, and all averages of any subset of its element, prove it contains all rational number between 0 and 1

answered Nov 25, 2015 at 23:12

1 vote

Find smallest number m such that $9^{32} + 19^{433} + m$ is divisible by $4$

answered Nov 28, 2012 at 3:47

1 vote

Puzzle about voting

answered Oct 3, 2013 at 21:59

1 vote

What does it mean for a group to "act algebraically"?

answered Sep 5, 2013 at 16:42

1 vote

Using "adjunction" to refer to the act of taking adjoints of operators

answered Jun 13, 2013 at 6:36

1 vote

Is the skill to learn new math by reading textbook alone (no lectures) required when one becomes a PhD student?

answered Dec 16, 2012 at 7:08

1 vote

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Finding $M$ such that $MMx*y$ modulo $2zM$ is 0?

answered Dec 3, 2012 at 19:02

0 votes

There exists integers such that 200s + 567t = 1. Find s.

answered Jan 23, 2016 at 23:16

0 votes

Sequent proof in propositional logic

answered Mar 8, 2017 at 10:12

0 votes

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What does it mean to "determine" an equivalence relation?

answered Oct 22, 2013 at 16:22

0 votes

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Show that any group of order 3025 is solvable

answered Oct 18, 2020 at 22:25

0 votes

Is the endomorphism ring of a module over a non-commutative ring always non-commutative?

answered Dec 15, 2019 at 23:48

0 votes

Property of twice of a vector minus its orthogonal projection

answered Jul 8, 2023 at 14:59

0 votes

Can the Euclidean unit interval have a finer connected topology?

answered May 14 at 15:03

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116 Answers

Find the number of pairs of two consecutive zeros

Define the sum of transfinite ordinal sequences according to finite ordinal sum.

On the reiteration (or repetition) rule in natural deduction: is the rule "obvious" or does it need a proof?

Replacing a family of epimorphisms by epimorphisms with the same domain by forming pullbacks in an abelian category

How do I show P(Z = z) if Z = X+Y, both random discrete variables.

Fundamental group of wedge of two projective planes

How to understand intuitively why "$\exists !x \exists !y$" is not equivalent to "$\exists !y \exists !x$"?

How to show that $\{(x, y) \in \mathbb{R}^2\mid\cos(x^2) + x^3 - 4 7y > e^x - y^2\}$ is open or closed?

How to show this ring homomorphism is surjective?

prove two different forms of the same uniqueness theorem are logically equivalent

Combining products of like terms in a division

XOR of Three Integers

A set contains $0$, $1$, and all averages of any subset of its element, prove it contains all rational number between 0 and 1

Find smallest number m such that $9^{32} + 19^{433} + m$ is divisible by $4$

Puzzle about voting

What does it mean for a group to "act algebraically"?

Using "adjunction" to refer to the act of taking adjoints of operators

Is the skill to learn new math by reading textbook alone (no lectures) required when one becomes a PhD student?

Finding $M$ such that $MMx*y$ modulo $2zM$ is 0?

There exists integers such that 200s + 567t = 1. Find s.

Sequent proof in propositional logic

What does it mean to "determine" an equivalence relation?

Show that any group of order 3025 is solvable

Is the endomorphism ring of a module over a non-commutative ring always non-commutative?

Property of twice of a vector minus its orthogonal projection

Can the Euclidean unit interval have a finer connected topology?