Timeline for Number of subsets with fixed cardinality k, and sum of elements a multiple of m
Current License: CC BY-SA 3.0
3 events
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| Sep 16, 2013 at 0:49 | comment | added | Douglas Zare | @Konstantinos Gaitanas: Apply that permutation to each element of the subset of size $k$. $p$ does not have to be less than $k$. For example, suppose you have the subset $\lbrace 4, 8,10 \rbrace$ with sum $22$ and $p=5$. $4 \mapsto 5, 8 \mapsto 9, 10 \mapsto 6$, so the subset maps to $\lbrace 5,9,6 \rbrace$. The sum of the new subset is $20 \equiv 22+3 \mod 5$. | |
| Sep 15, 2013 at 22:26 | comment | added | Konstantinos Gaitanas | ''applying the permutation (1 2 ... p)(p+1 p+2 ... 2p)... to a subset of size k adds k to the sum modp'' what exactly do you mean?shouldn't then p be less or equal to k? | |
| Sep 15, 2013 at 21:53 | history | answered | Douglas Zare | CC BY-SA 3.0 |