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Hello, I am a freshman at The National Autonomous University of Mexico (UNAM).

My interests are contest problems,elementary number theory, combinatorics, graph theory, linear algebra, group theory, abstract algebra and I have been meaning to learn category theory and matroids.


Dec
6
comment Baire's property iff first category has dense complement.
Oh, thanks, I had heard that one referred to as baby Rudin.
Dec
6
comment Baire's property iff first category has dense complement.
which one of them?
Dec
6
comment Baire's property iff first category has dense complement.
Do you recommend a text?
Dec
6
comment Baire's property iff first category has dense complement.
Where can I read about this topic?
Dec
6
answered recurrence relation sequence..stuck
Dec
6
comment Elementary set theory question (not a rational set)
should it be $(A\cup B)^c$ or is it ok like that?
Dec
6
answered $f$ is a continuous function from $[0,1]$ to $\mathbb{R}$ s.t. $f(0)=f(1)$, prove $\exists c$ in $[0,\frac{1}{2}]$ such that $f(c)=f(c+ \frac{1}{2})$
Dec
6
comment Solve the following trig equation
Oh dang, my bad I'm so sorry. Thank you @HenningMakholm
Dec
6
comment Solve the following trig equation
Don't they force you to learn a table with what are deemed "important" values of the cosine function in your school?
Dec
6
revised How can I prove analytically the number $2^{100000}+1$ is not prime??
edited body
Dec
6
answered Solve the following trig equation
Dec
6
comment Can a smooth function on the reals form a non-commutative semigroup?
you don't have to accept my answer if you don't want to. Let me see if I can find a different example.
Dec
6
comment Can a smooth function on the reals form a non-commutative semigroup?
You should have said that earlier, there is also right identities.
Dec
6
comment Can a smooth function on the reals form a non-commutative semigroup?
oh, sorry I haven't taken calculus yet, is that function not smooth?
Dec
6
answered Can a smooth function on the reals form a non-commutative semigroup?
Dec
5
revised How can I prove analytically the number $2^{100000}+1$ is not prime??
added 9 characters in body
Dec
5
revised How can I prove analytically the number $2^{100000}+1$ is not prime??
added 111 characters in body
Dec
5
answered How can I prove analytically the number $2^{100000}+1$ is not prime??
Dec
5
answered IfA is an upper triangular n x n matrix, then det(A) is not equal to 0 . Why is this false?
Dec
5
comment Example of an associative binary operation, without identities or inverses.
the identity matrix is not strictly upper triangular