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3 votes
2 answers
397 views

An "incomplete" tiling?

Given an $m\times n$ chess board, we place $p$ $2\times 1$ dominoes on the board so that they don't overlap. How many ways can we place them? When each square of the board is covered by a domino this ...
JJJZZZZZ's user avatar
  • 380
1 vote
0 answers
94 views

Number of extremal $\{0,1\}$ matrices having permanent $1$ property

Is there a function which describes the number of $\{0,1\}^{n\times n}\cap\mathbb Z^{n\times n}$ matrices having permanent $1$? I think it might be $\mathsf{poly}(n!)$ bounded. Is there a function ...
Turbo's user avatar
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7 votes
2 answers
480 views

Are all numbers from $1$ to $n!$ the number of perfect matchings of some bipartite graph?

Let $f(G)$ give the number of perfect matchings of a graph $G$. Consider set $\mathcal N_{2n}=\{0,1,2,\dots,n!-1,n!\}$. Consider collection of all $2n$ vertex balanced bipartite graph to be $\...
Turbo's user avatar
  • 13.9k