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location Monkey Island, OK
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visits member for 2 years, 3 months
seen 40 mins ago

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.


23h
answered Total probability
23h
answered Special Arrangement
1d
comment Is there such a thing as the Fundamental Theorem of ZFC?
I don't think most people here are familiar with the game of ZFC. Could you state what the rules are please?
1d
comment Is this calculus proof I came up with sound?
I made a small mistake with the indexes, I think it is ok now. Am I right the proof is fine now as is? Thank you David.
1d
revised Is this calculus proof I came up with sound?
added 19 characters in body
1d
comment Is this calculus proof I came up with sound?
I should be more precise? I'm no expert, but do intervals like that make sense on complex numbers?
1d
asked Is this calculus proof I came up with sound?
1d
revised What is the smallest natural number n?
deleted 36 characters in body
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awarded  Popular Question
Sep
18
comment Probability: Distinguishable vs Indistinguishable
oh, I should have written $5/9$ since we want the complement of what I had, it is the same as the sum you wrote, only computed in a slightly different way
Sep
18
comment Probability: Distinguishable vs Indistinguishable
I don't even see why the method for selecting the balls matters. Wouldn't it be the same to say: pick two distinct balls, what's the probability they are of the same color, since there are $9\cdot8/2$ ways to select 2 distinct balls and $5\cdot4/2+4*3/2$ ways to select of the same color we get the probability is $16/36=4/9$
Sep
18
revised Truth table and the meaning of $\oplus$ in propositional logic
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Sep
18
answered Truth table and the meaning of $\oplus$ in propositional logic
Sep
17
asked placing chess knights in a numbered chessboard.
Sep
16
answered The larger of two supplementary angles exceeds 7 times the smaller by 4 degrees. Find the measure of the angle.
Sep
16
comment Can a game with negative expectation still have a positive utility?
yes, the reason why economists sometimes want their utilities to be concave down is because this means they are "against risk", and at least in the algebra of words "against risk" would imply players would never want to play if the expected value was non-positive.
Sep
16
answered Can a game with negative expectation still have a positive utility?
Sep
13
accepted Calculating $\sum_{k=1}^nk(k!)$ combinatorially
Sep
13
comment Calculating $\sum_{k=1}^nk(k!)$ combinatorially
I meant that each term was going to be $(k+1)!-k!$
Sep
13
comment Distribute n identical objects into r distinct groups
It foesn't, if two overlap it means that there are no stars between those bars. If you want to ensure at least 1 for each category just take away 1 star for each category and do the same. so the formula would be $\binom{k-1}{n-1}$