Permutations, combinations, bijective proofs, generating functions
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vote
0answers
33 views
+50
Finding the shortest/“most negative” closed directed trail in a weighted digraph with negative weights
I'm using the following definition of a "closed directed trail": a closed directed trail is a directed cycle in a digraph where all edges are distinct. Note that vertices may be repeated, so long as ...
2
votes
1answer
170 views
+50
Lottery with coupon collecting - what prices are fair?
Assume there is a lottery where you can buy lots for 1\$ each. To win the grand price you have to collect $n$ different coupons $C_1, \ldots, C_n$ where $C_i$ occurs with probability $p_i$. You may ...
