22,692 reputation
43168
bio website ie.linkedin.com/in/aymanh
location Dublin, Ireland
age
visits member for 3 years, 9 months
seen 47 mins ago

Senior software engineer at Google. B.Sc. and M.Sc. in Computer Science, Software Engineering.


9h
revised What formula will tell if three vertices in 3d space are ordered clockwise or counter-clockwise from the point of view of a camera?
edited tags
17h
comment showing that maps from circle to circle are not homotopic
Worth checking anyway. If one avoids fundamental groups, I suspect one will have to follow similar steps in the proof regardless.
18h
comment showing that maps from circle to circle are not homotopic
As for your question, do you consider comparing induced maps on the fundamental group elementary enough?
18h
comment showing that maps from circle to circle are not homotopic
Hi Kenneth, you've asked 12 questions on this site during the last couple of months. Each time, another site member edited your question to render mathematical notation via MathJax. Would you please take some time to do it yourself? This will make your questions easier to read and answer. See this for a tutorial. Also, if you find an answer useful, you can accept it. This marks the question as resolved and rewards the user who took time to help. See this for a tutorial.
20h
comment uniform continuity of a function
$[0, 1]$ is compact and it contains $(0, 1)$.
20h
comment uniform continuity of a function
Do you know that continuous functions on compact sets are uniformly continuous?
1d
revised By completing the square, the expression x^2+8 x +142 equals (x+A)^2+B . What do A and B equal?
edited tags
1d
comment Mapping on induced topology and distance metric
What's the context of this question? Where did you come across it?
2d
comment Soft question regarding real analysis
@mathwonk Chapters 1-7 are essential. 8-9 are good to have. 10-11 are better studied elsewhere. For example, Rudin's Real & Complex Analysis offers a better intro to Lebesgue integration.
2d
comment $ker (T \otimes id_{Z})=ker(T)\otimes Z$
@anomaly I guessed as much. Still, the answer can serve as a motivation for flat modules. Also, it might be useful for others who read this question.
2d
answered $ker (T \otimes id_{Z})=ker(T)\otimes Z$
Sep
13
comment Automorphisms of the group of integers $\mathbb Z$
Since $\varphi(n) = n \varphi(1)$, we have $\varphi(\mathbb Z) = \varphi(1) \mathbb Z$. Only for $\varphi(1) \in \{1, -1\}$ we have $\varphi(1) \mathbb Z = \mathbb Z$. Does it make sense now?
Sep
13
revised Automorphisms of the group of integers $\mathbb Z$
Better title
Sep
13
answered Automorphisms of the group of integers $\mathbb Z$
Sep
13
comment Automorphisms of the group of integers $\mathbb Z$
I presume you're considering group automorphisms here?
Sep
12
revised “Reverse” quotients.
Fixed spacing around \sim
Sep
12
comment Compatible intersecting coordinate patches must map to the same dimensional $\mathbb R^n$.
It's essentially the same argument as the accepted answer below, but using fancier language.
Sep
12
comment Fundamental group of a kite shaped grid
Yes, it does. Alternatively, you can calculate the Euler characteristic and use that to compute $H_1$ and hence $\pi_1$. This method is useful for more complicated graphs.
Sep
12
answered Equality of ideals and their vareties.
Sep
12
comment Prove that if $X \subset [a,b]$ isn't a measure-zero set, then there exists $\varepsilon >0$
You need to explain why the existence of $\epsilon$ is justified. (Second sentence in the solution.) It's also unclear why the given intervals form a partition of $P$. The argument can be simplified: Assume that such a partition exists, and find a lower bound for the measure in question by using the fact that $X$ has positive measure.