User José Marín

24 votes

4 answers

4k views

How is possible that those shapes are equivalent in topology?

asked Aug 25, 2018 at 19:00

6 votes

1 answer

173 views

What is the name of this surface? (appears in a movie)

asked Aug 19, 2020 at 20:56

4 votes

2 answers

120 views

Which is the mark that the competent mathematician must have more than any other? [closed]

asked Feb 12, 2020 at 22:17

3 votes

2 answers

376 views

If we know the congruence of the apex and the base of two isosceles, are both congruent triangles? (help with the proof)

asked Jan 3, 2021 at 3:54

3 votes

2 answers

481 views

Understand the quotient group

asked Apr 7, 2019 at 0:17

3 votes

1 answer

179 views

calculate the ideal generated by $\langle2,x\rangle$ [duplicate]

asked Apr 10, 2019 at 11:38

2 votes

1 answer

104 views

If $f$ belongs to $M^{+} $ and $c \ge 0$ then $cf$ belongs to $M^{+}$ and $ \int cf = c\int f$

asked Apr 9, 2019 at 7:28

2 votes

1 answer

1k views

What does $f = g$ almost everywhere mean?

asked Mar 22, 2019 at 19:41

2 votes

1 answer

191 views

what is the measure of the set $[0,\infty)$?

asked Jul 8, 2019 at 14:51

2 votes

1 answer

513 views

How to calculate an integral given a measure?

asked Jun 4, 2019 at 14:39

1 vote

0 answers

54 views

Let $(f_n)$ be a sequence in $M^+(\mathbb{R})$ proove that $ \displaystyle{\int \sum_{n=1}^{\infty}f_n = \sum_{n=1}^{\infty}\int f_n}$

asked May 14, 2019 at 6:36

1 vote

1 answer

2k views

Can unbounded functions be Lebesgue integrable?

asked Jun 24, 2019 at 5:48

1 vote

0 answers

67 views

Does anyone have this book to share? [Julia, A Life in Mathematics. By Constance Reid]

asked Jul 28, 2020 at 20:04

1 vote

2 answers

102 views

calculate the sum $\sum 2^{-n} (\frac 1 n -\frac 1 {n+1})$ [duplicate]

asked Jun 24, 2019 at 6:49

1 vote

1 answer

63 views

How much precise are the Google maps coordinates? [closed]

asked Jun 28, 2019 at 5:29

1 vote

2 answers

2k views

Is the criterion SAA of congruent triangles valid?

asked Aug 24, 2020 at 21:50

1 vote

4 answers

95 views

Why is: $1+2+2^2+\cdots+2^{n-2} = 2^{n-1}-1$?

asked Jun 3, 2019 at 15:40

1 vote

1 answer

67 views

Prove that a function that is equal almost everywere to a measurable function is measurable

asked Mar 23, 2019 at 6:00

1 vote

2 answers

24 views

$ A = (A\cap E^c) \cup (A\cap E)$?

asked Mar 23, 2019 at 17:21

1 vote

1 answer

48 views

How to prove that the convergent value of a sequence is unique?

asked Mar 26, 2019 at 0:40

1 vote

1 answer

344 views

What exactly is a superior and inferior of a sequence of function?

asked Mar 26, 2019 at 2:45

1 vote

1 answer

147 views

A function $ f: [a,b] \rightarrow \mathbb{R} $ strictly increasing is continous in [a,b]?

asked Mar 20, 2019 at 3:50

1 vote

3 answers

3k views

Let be $G$ a group and $a,b \in G$. Prove that $ (ab) ^{-1} = b^{-1}a^{-1}$

asked Apr 8, 2019 at 3:04

1 vote

2 answers

47 views

Definition of Subgroup

asked Mar 27, 2019 at 1:22

1 vote

1 answer

26 views

Determine $\langle\bigcup_{\alpha \in \mathbb{I}} B_{\alpha}\rangle$

asked Apr 6, 2019 at 17:09

1 vote

1 answer

70 views

What is $A^B$ when B has a finite cardinality?

asked Apr 8, 2019 at 23:02

1 vote

2 answers

52 views

How to prove that in an abelian group $-(-a) = a$?

asked Apr 30, 2019 at 4:35

1 vote

1 answer

127 views

Show that $\mathbb{Z}[x]/\langle2x-1\rangle$ and $\mathbb{Z}[1/2]$ are isomorphic rings. [duplicate]

asked May 8, 2019 at 10:56

0 votes

2 answers

272 views

Prove that $f$ is not Lebesgue integrable

asked May 14, 2019 at 3:23

0 votes

1 answer

2k views

is $1/x$ a measurable function on $(0,1)$?

asked May 14, 2019 at 4:05

Stack Exchange Network

68 Questions

How is possible that those shapes are equivalent in topology?

What is the name of this surface? (appears in a movie)

Which is the mark that the competent mathematician must have more than any other? [closed]

If we know the congruence of the apex and the base of two isosceles, are both congruent triangles? (help with the proof)

Understand the quotient group

calculate the ideal generated by $\langle2,x\rangle$ [duplicate]

If $f$ belongs to $M^{+} $ and $c \ge 0$ then $cf$ belongs to $M^{+}$ and $ \int cf = c\int f$

What does $f = g$ almost everywhere mean?

what is the measure of the set $[0,\infty)$?

How to calculate an integral given a measure?

Let $(f_n)$ be a sequence in $M^+(\mathbb{R})$ proove that $ \displaystyle{\int \sum_{n=1}^{\infty}f_n = \sum_{n=1}^{\infty}\int f_n}$

Can unbounded functions be Lebesgue integrable?

Does anyone have this book to share? [Julia, A Life in Mathematics. By Constance Reid]

calculate the sum $\sum 2^{-n} (\frac 1 n -\frac 1 {n+1})$ [duplicate]

How much precise are the Google maps coordinates? [closed]

Is the criterion SAA of congruent triangles valid?

Why is: $1+2+2^2+\cdots+2^{n-2} = 2^{n-1}-1$?

Prove that a function that is equal almost everywere to a measurable function is measurable

$ A = (A\cap E^c) \cup (A\cap E)$?

How to prove that the convergent value of a sequence is unique?

What exactly is a superior and inferior of a sequence of function?

A function $ f: [a,b] \rightarrow \mathbb{R} $ strictly increasing is continous in [a,b]?

Let be $G$ a group and $a,b \in G$. Prove that $ (ab) ^{-1} = b^{-1}a^{-1}$

Definition of Subgroup

Determine $\langle\bigcup_{\alpha \in \mathbb{I}} B_{\alpha}\rangle$

What is $A^B$ when B has a finite cardinality?

How to prove that in an abelian group $-(-a) = a$?

Show that $\mathbb{Z}[x]/\langle2x-1\rangle$ and $\mathbb{Z}[1/2]$ are isomorphic rings. [duplicate]

Prove that $f$ is not Lebesgue integrable

is $1/x$ a measurable function on $(0,1)$?