# Jorge Fernández

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bio website location Mexico City age member for 2 years, 6 months seen 3 hours ago profile views 1,985

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.

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 Dec6 comment Baire's property iff first category has dense complement. Oh, thanks, I had heard that one referred to as baby Rudin. Dec6 comment Baire's property iff first category has dense complement. which one of them? Dec6 comment Baire's property iff first category has dense complement. Do you recommend a text? Dec6 comment Baire's property iff first category has dense complement. Where can I read about this topic? Dec6 answered recurrence relation sequence..stuck Dec6 comment Elementary set theory question (not a rational set) should it be $(A\cup B)^c$ or is it ok like that? Dec6 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 $f(c)=f(c+ \frac{1}{2})$ Dec6 comment Solve the following trig equation Oh dang, my bad I'm so sorry. Thank you @HenningMakholm Dec6 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? Dec6 revised How can I prove analytically the number $2^{100000}+1$ is not prime?? edited body Dec6 answered Solve the following trig equation Dec6 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. Dec6 comment Can a smooth function on the reals form a non-commutative semigroup? You should have said that earlier, there is also right identities. Dec6 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? Dec6 answered Can a smooth function on the reals form a non-commutative semigroup? Dec5 revised How can I prove analytically the number $2^{100000}+1$ is not prime?? added 9 characters in body Dec5 revised How can I prove analytically the number $2^{100000}+1$ is not prime?? added 111 characters in body Dec5 answered How can I prove analytically the number $2^{100000}+1$ is not prime?? Dec5 answered IfA is an upper triangular n x n matrix, then det(A) is not equal to 0 . Why is this false? Dec5 comment Example of an associative binary operation, without identities or inverses. the identity matrix is not strictly upper triangular