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visits member for 3 years, 2 months
seen Jul 22 at 20:43

Jul
22
comment How many different choice of sets?
This is very clear, thank you!
Jul
22
comment How many different choice of sets?
this is definitely true, but the problem is how to simplify it.
Jul
19
awarded  Curious
Jul
18
comment How many different choice of sets?
could you please explain a bit why is that?
Jul
18
comment How many different choice of sets?
$i≠j⇒Si∩Sj=∅$ is not demanded. Only when $i=j+1,Si∩Sj=∅$ is demanded. And permutations of $S_i$ is counted.
Jul
18
revised How many different choice of sets?
deleted 2 characters in body
Jul
18
awarded  Commentator
Jul
18
comment How many different choice of sets?
Sorry I do forget to add the condition that S_i is nonempty. But I do not think the first answer is correct anyway.
Jul
18
revised How many different choice of sets?
added 30 characters in body
Jul
18
asked How many different choice of sets?
Jul
16
revised How many positive integer solutions are there to the inequality $x_1+x_2+…+x_r\le n$?
added 122 characters in body
Jul
16
comment How many positive integer solutions are there to the inequality $x_1+x_2+…+x_r\le n$?
smart answer! Thank you!
Jul
16
asked How many positive integer solutions are there to the inequality $x_1+x_2+…+x_r\le n$?
Jan
25
answered edge coloring of a specific graph
Jan
24
comment edge coloring of a specific graph
Yes, Hagen's explanation is what I really mean.
Jan
24
asked edge coloring of a specific graph
Sep
9
asked Order embedding and graph embedding of Hasse digraphs
Dec
5
awarded  Supporter
Nov
28
comment The application of Doob's inequality and Doob's decomposition theorem
thanks @StefanHansen
Nov
28
revised The application of Doob's inequality and Doob's decomposition theorem
added 484 characters in body