71 reputation
6
bio website
location Kolkata, India
age 24
visits member for 2 years, 5 months
seen 10 hours ago

Hi.i am a student of computer science and engineering department.I am currently completing my bachelor degree from Jadavpur University,kolkata, India.


2d
comment proving an invloved combinatorial identity
$|P_{i_1} \bigcap P_{i_2}|=m^2(m+1)^{n−4}C_{i_2}$, where $C_{i_1}$ represents choices to put the j of the definition of $P_{i_1}$. did you accidentally put $C_{i_2}$ instead of $C_{i_1}$?
2d
comment proving an invloved combinatorial identity
Hi Phicar, could you please explain a little bit this particular line "I think that you just need one position to put the j of the first element of the chosen by the inclusion exclusion (i.e. a1)".
2d
revised proving an invloved combinatorial identity
added 73 characters in body
2d
comment proving an invloved combinatorial identity
:) good question. But unfortunately the answer is yes.
Oct
28
comment Combinatorial proof of an identity related to Derangements
If you look carefully, number of 1-off derangements is equal to $(n-1)d(n-2)$; You first select fixed position in ${n-1}$ ways and rest elements can be dearranged in d(n-2) ways. So, proving that there are $d(n-1)+ (-1)^n$ 1-off-derangements of length n-1 is equivalent to proving the initial problem. $d(n-1)+ (-1)^n = (n-1)d(n-2) $ $\Rightarrow d(n-1) = (n-1)d(n-2) + (-1)^{n-1}$
Oct
28
comment proving an invloved combinatorial identity
i just changed the power of (m+1) in the L.H.S . That was a mistake made by me.
Oct
28
revised proving an invloved combinatorial identity
fixing the identity
Oct
28
asked proving an invloved combinatorial identity
Oct
28
revised Combinatorial proof of an identity related to Derangements
added 23 characters in body
Oct
28
comment Combinatorial proof of an identity related to Derangements
I guess you got the question wrong. I am interested in proving the recurrence relation.
Oct
28
revised Combinatorial proof of an identity related to Derangements
added 4 characters in body
Oct
28
asked Combinatorial proof of an identity related to Derangements
Oct
22
answered Put B balls in C containers. How many combinations have box(es) with exactly 2 balls?
Oct
21
awarded  Tumbleweed
Oct
14
awarded  Editor
Oct
14
revised Combinatorial proof of an identity of Striling number of first kind
added 120 characters in body
Oct
14
asked Combinatorial proof of an identity of Striling number of first kind
Sep
24
awarded  Autobiographer
Jul
18
comment Flaw in the proof that a set is countable
Yup, thanks for pointing. Got it.
Jul
18
asked Flaw in the proof that a set is countable