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Dec
12
awarded  Notable Question
Dec
11
accepted A sequence of roots of polynomials depending on an integer parameter
Dec
11
revised A sequence of roots of polynomials depending on an integer parameter
edited body
Dec
11
comment A sequence of roots of polynomials depending on an integer parameter
@Daneil R Actually we want to show that $Q_n(x_n)=1$. I edited the question thanks.
Dec
11
asked A sequence of roots of polynomials depending on an integer parameter
Dec
3
awarded  Popular Question
Nov
15
awarded  Popular Question
Sep
30
awarded  Explainer
Sep
27
comment The number of $p$-subsets of an $n$-set is $n$ choose $p$
It is $\dfrac{n!}{p!(n-p)!}$
Sep
27
revised The number of $p$-subsets of an $n$-set is $n$ choose $p$
added 1 character in body
Sep
27
asked The number of $p$-subsets of an $n$-set is $n$ choose $p$
Sep
25
comment An injective map between two sets of the same cardinality is bijective.
Thank you very much!!
Sep
25
accepted An injective map between two sets of the same cardinality is bijective.
Sep
25
comment An injective map between two sets of the same cardinality is bijective.
Chevalier et Oudot - "Maths MPSI, H prepa tout en un" page 172.
Sep
24
comment Restatement of a result on the gcd of two integers.
yes exactly, that's the notation for lcm !!
Sep
24
comment Restatement of a result on the gcd of two integers.
This notation of gcd is very common in french mathematical litterature.
Sep
24
asked Restatement of a result on the gcd of two integers.
Sep
24
comment An injective map between two sets of the same cardinality is bijective.
yes i see that but why the author does not suppose this hypothesis when talking about surjectivity in the same theorem!! The book is in french and it is rather a very well known book in the french mathematical litterature.
Sep
24
comment An injective map between two sets of the same cardinality is bijective.
I think it can't be that reason because in the same theorem weh have just after this statement : If $card(E)=card(F)$ then a surjective map is bijective (without the condition of $\not = 0$)
Sep
24
asked An injective map between two sets of the same cardinality is bijective.