Permanents and determinants of (0,1) matrices

all at abouthugo.de all at abouthugo.de
Mon Nov 3 01:34:01 CET 2003


Jaap Spies <j.spies at hccnet.nl> schrieb am 02.11.2003, 02:13:11:
> Jaap Spies wrote:
> > Yuval Dekel wrote:

> >> a(n) = number of different values taken by permanents of nonsingular 
> >> nxn (0,1) matrices ,
> >> b(n) = number of different values taken by determinants of nxn (0,1) 
> >> matrices .
> >>
[...] 
> Here are my new results
> 
> n=1
> {1, 1}
> n=2
> {1, 6}
> n=3
> {1, 150}, {2, 6}, {3, 18}
> n=4
> {1, 13032}, {2, 1440}, {3, 4992}, {4, 672}, {5, 1440}, {6, 288}, {7, 576}
> {9, 24}, {11, 96}
> n=5
> {1, 3513720}, {2, 693840}, {3, 2626800}, {4, 604200}, {5, 1451400}, {6, 468000}
> {7, 962400}, {8, 252000}, {9, 425400}, {10, 190800}, {11, 379200}, {12, 97200}
> {13, 205440}, {14, 100800}, {15, 132000}, {16, 28800}, {17, 108000}, {18, 28800}
> {19, 44400}, {20, 33600}, {21, 61200}, {22, 9600}, {23, 14400}, {25, 36000}
> {26, 7200}, {29, 14400}, {31, 14400}, {33, 2400}, {39, 7200}, {44, 120}, {53, 600}
> 
> So a(1)=1, a(2)=1, a(3)=3, a(4)=9, a(5)=31, ...,
> 
> a(6) is hard to get.
> 
> Jaap Spies

SeqFans,

independent verification never hurts, so here are my
results, which agree perfectly with those of Jaap (column 4)
I have included also the counts for the permanents
of all (0,1)-matrices (column 3) and for the singular
(0,1) matrices (column 5).

The last column also makes a new sequence:

Different permanents of singular (0,1) matrices (starting at 1)
1 2 4 10 32

I hope this table does not violate Gerard's length limit by an
intolerable amount; sorry.

 Value
    |       Number of (0,1) matrices with det=value
    |          |      Number of matrices with permanent=value
    |          |          |      Number of matrices with
    |          |          |      det /=0 and permanent=value
    |          |          |          |      Number of matrices
    |          |          |          |      with det=0 and
    |          |          |          |      permanent=value

 N: 2
   -1          3          0          0          0
    0         10          9          0          9
    1          3          6          6          0
    2          0          1          0          1

 N: 3
   -2          3          0          0          0
   -1         84          0          0          0
    0        338        265          0        265
    1         84        150        150          0
    2          3         69          6         63
    3          0         18         18          0
    4          0          9          0          9
    6          0          1          0          1

 N: 4
   -3         60          0          0          0
   -2       1200          0          0          0
   -1      10020          0          0          0
    0      42976      27713          0      27713
    1      10020      13032      13032          0
    2       1200      10800       1440       9360
    3         60       4992       4992          0
    4          0       4254        672       3582
    5          0       1440       1440          0
    6          0       1536        288       1248
    7          0        576        576          0
    8          0        648          0        648
    9          0         24         24          0
   10          0        288          0        288
   11          0         96         96          0
   12          0         48          0         48
   14          0         72          0         72
   18          0         16          0         16
   24          0          1          0          1

 N: 5
   -5       3600          0          0          0
   -4      43560          0          0          0
   -3     144720          0          0          0
   -2    1213920          0          0          0
   -1    4851360          0          0          0
    0   21040112   10363361          0   10363361
    1    4851360    3513720    3513720          0
    2    1213920    4339440     693840    3645600
    3     144720    2626800    2626800          0
    4      43560    3015450     604200    2411250
    5       3600    1451400    1451400          0
    6          0    1872800     468000    1404800
    7          0     962400     962400          0
    8          0    1295700     252000    1043700
    9          0     425400     425400          0
   10          0     873000     190800     682200
   11          0     379200     379200          0
   12          0     514300      97200     417100
   13          0     205440     205440          0
   14          0     437400     100800     336600
   15          0     132000     132000          0
   16          0     206550      28800     177750
   17          0     108000     108000          0
   18          0     212200      28800     183400
   19          0      44400      44400          0
   20          0     119550      33600      85950
   21          0      61200      61200          0
   22          0      69600       9600      60000
   23          0      14400      14400          0
   24          0      82475          0      82475
   25          0      36000      36000          0
   26          0      33000       7200      25800
   28          0      32400          0      32400
   29          0      14400      14400          0
   30          0      18400          0      18400
   31          0      14400      14400          0
   32          0      24300          0      24300
   33          0       2400       2400          0
   34          0       5400          0       5400
   36          0      11300          0      11300
   38          0       7200          0       7200
   39          0       7200       7200          0
   40          0       5400          0       5400
   42          0       4400          0       4400
   44          0        120        120          0
   46          0       3600          0       3600
   48          0       1600          0       1600
   50          0       3600          0       3600
   53          0        600        600          0
   54          0        400          0        400
   60          0       1200          0       1200
   64          0        600          0        600
   72          0        100          0        100
   78          0        200          0        200
   96          0         25          0         25
  120          0          1          0          1

n=6: Computing the determinants of all 2^36 6X6 (0,1) matrices took
~6 days CPU on a 500 MHz Digital Alphastation (using Gauss elimination).
I'll not try the permanents ... maybe someone else in this group with
more powerful resources could attack this problem? 

Hugo





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