par Anonyme » 30 Avr 2005, 17:14
Le Fri, 30 Apr 2004 12:47:10 +0100, Pierre Capdevila à écrit
>Bonjour
>
>Voici un problème qu'on m'a posé et sur lequel je sèche...
>
>Soit E un ensemble de cardinal n.
>
>Soit p cardinal p. On sait que Card F = C(n,p)
>
>Soit p de cardinal k. On sait que Card G = C(n,k)
>
>Question :
>
>Comment construire H, sous-ensemble de G, tel que
>tout élément F soit inclus dans au moins un élément de
>H et tel que Card H soit le plus petit possible ?
>Que vaut Card H ?
>
>Merci,
>Pierre
>
J'ai remis un peu le nez dans ce problème, mais je ne trouve pas de
formule explicite.
Pour m'aider j'ai fait un petit programme qui fait les dénombrements
pour moi, en espérant que cela me donne un idée théorique...
Voici ce à quoi je suis parvenu pour le moment :
*******************************************
n = 1
nb = 1 1
#(1,1) = 1
*******************************************
n = 2
nb = 1 1
nb = 1 2
#(1,1) = 2
nb = 2 12
#(1,2) = 1
nb = 1 12
#(2,2) = 1
*******************************************
n = 3
nb = 1 1
nb = 1 2
nb = 1 3
#(1,1) = 3
nb = 2 12
nb = 1 13
#(1,2) = 2
nb = 3 123
#(1,3) = 1
nb = 1 12
nb = 1 13
nb = 1 23
#(2,2) = 3
nb = 3 123
#(2,3) = 1
nb = 1 123
#(3,3) = 1
*******************************************
n = 4
nb = 1 1
nb = 1 2
nb = 1 3
nb = 1 4
#(1,1) = 4
nb = 2 12
nb = 2 34
#(1,2) = 2
nb = 3 123
nb = 1 124
#(1,3) = 2
nb = 4 1234
#(1,4) = 1
nb = 1 12
nb = 1 13
nb = 1 23
nb = 1 14
nb = 1 24
nb = 1 34
#(2,2) = 6
nb = 3 123
nb = 2 124
nb = 1 134
#(2,3) = 3
nb = 6 1234
#(2,4) = 1
nb = 1 123
nb = 1 124
nb = 1 134
nb = 1 234
#(3,3) = 4
nb = 4 1234
#(3,4) = 1
nb = 1 1234
#(4,4) = 1
*******************************************
n = 5
nb = 1 1
nb = 1 2
nb = 1 3
nb = 1 4
nb = 1 5
#(1,1) = 5
nb = 2 12
nb = 2 34
nb = 1 15
#(1,2) = 3
nb = 3 123
nb = 2 145
#(1,3) = 2
nb = 4 1234
nb = 1 1235
#(1,4) = 2
nb = 5 12345
#(1,5) = 1
nb = 1 12
nb = 1 13
nb = 1 23
nb = 1 14
nb = 1 24
nb = 1 34
nb = 1 15
nb = 1 25
nb = 1 35
nb = 1 45
#(2,2) = 10
nb = 3 123
nb = 3 145
nb = 2 234
nb = 2 235
#(2,3) = 4
nb = 6 1234
nb = 3 1235
nb = 1 1245
#(2,4) = 3
nb = 10 12345
#(2,5) = 1
nb = 1 123
nb = 1 124
nb = 1 134
nb = 1 234
nb = 1 125
nb = 1 135
nb = 1 235
nb = 1 145
nb = 1 245
nb = 1 345
#(3,3) = 10
nb = 4 1234
nb = 3 1235
nb = 2 1245
nb = 1 1345
#(3,4) = 4
nb = 10 12345
#(3,5) = 1
nb = 1 1234
nb = 1 1235
nb = 1 1245
nb = 1 1345
nb = 1 2345
#(4,4) = 5
nb = 5 12345
#(4,5) = 1
nb = 1 12345
#(5,5) = 1
*******************************************
n = 6
nb = 1 1
nb = 1 2
nb = 1 3
nb = 1 4
nb = 1 5
nb = 1 6
#(1,1) = 6
nb = 2 12
nb = 2 34
nb = 2 56
#(1,2) = 3
nb = 3 123
nb = 3 456
#(1,3) = 2
nb = 4 1234
nb = 2 1256
#(1,4) = 2
nb = 5 12345
nb = 1 12346
#(1,5) = 2
nb = 6 123456
#(1,6) = 1
nb = 1 12
nb = 1 13
nb = 1 23
nb = 1 14
nb = 1 24
nb = 1 34
nb = 1 15
nb = 1 25
nb = 1 35
nb = 1 45
nb = 1 16
nb = 1 26
nb = 1 36
nb = 1 46
nb = 1 56
#(2,2) = 15
nb = 3 123
nb = 3 145
nb = 3 246
nb = 3 356
nb = 1 134
nb = 1 125
nb = 1 126
#(2,3) = 7
nb = 6 1234
nb = 5 1256
nb = 4 3456
#(2,4) = 3
nb = 10 12345
nb = 4 12346
nb = 1 12356
#(2,5) = 3
nb = 15 123456
#(2,6) = 1
nb = 1 123
nb = 1 124
nb = 1 134
nb = 1 234
nb = 1 125
nb = 1 135
nb = 1 235
nb = 1 145
nb = 1 245
nb = 1 345
nb = 1 126
nb = 1 136
nb = 1 236
nb = 1 146
nb = 1 246
nb = 1 346
nb = 1 156
nb = 1 256
nb = 1 356
nb = 1 456
#(3,3) = 20
nb = 4 1234
nb = 4 1256
nb = 4 3456
nb = 2 1235
nb = 2 1245
nb = 2 1236
nb = 2 1246
#(3,4) = 7
nb = 10 12345
nb = 6 12346
nb = 3 12356
nb = 1 12456
#(3,5) = 4
nb = 20 123456
#(3,6) = 1
nb = 1 1234
nb = 1 1235
nb = 1 1245
nb = 1 1345
nb = 1 2345
nb = 1 1236
nb = 1 1246
nb = 1 1346
nb = 1 2346
nb = 1 1256
nb = 1 1356
nb = 1 2356
nb = 1 1456
nb = 1 2456
nb = 1 3456
#(4,4) = 15
nb = 5 12345
nb = 4 12346
nb = 3 12356
nb = 2 12456
nb = 1 13456
#(4,5) = 5
nb = 15 123456
#(4,6) = 1
nb = 1 12345
nb = 1 12346
nb = 1 12356
nb = 1 12456
nb = 1 13456
nb = 1 23456
#(5,5) = 6
nb = 6 123456
#(5,6) = 1
nb = 1 123456
#(6,6) = 1
*******************************************
n = 7
nb = 1 1
nb = 1 2
nb = 1 3
nb = 1 4
nb = 1 5
nb = 1 6
nb = 1 7
#(1,1) = 7
nb = 2 12
nb = 2 34
nb = 2 56
nb = 1 17
#(1,2) = 4
nb = 3 123
nb = 3 456
nb = 1 127
#(1,3) = 3
nb = 4 1234
nb = 3 1567
#(1,4) = 2
nb = 5 12345
nb = 2 12367
#(1,5) = 2
nb = 6 123456
nb = 1 123457
#(1,6) = 2
nb = 7 1234567
#(1,7) = 1
nb = 1 12
nb = 1 13
nb = 1 23
nb = 1 14
nb = 1 24
nb = 1 34
nb = 1 15
nb = 1 25
nb = 1 35
nb = 1 45
nb = 1 16
nb = 1 26
nb = 1 36
nb = 1 46
nb = 1 56
nb = 1 17
nb = 1 27
nb = 1 37
nb = 1 47
nb = 1 57
nb = 1 67
#(2,2) = 21
nb = 3 123
nb = 3 145
nb = 3 246
nb = 3 356
nb = 3 347
nb = 3 257
nb = 3 167
#(2,3) = 7
nb = 6 1234
nb = 6 1567
nb = 4 2356
nb = 3 2347
nb = 2 1456
#(2,4) = 5
nb = 10 12345
nb = 7 12367
nb = 4 14567
#(2,5) = 3
nb = 15 123456
nb = 5 123457
nb = 1 123467
#(2,6) = 3
nb = 21 1234567
#(2,7) = 1
nb = 1 123
nb = 1 124
nb = 1 134
nb = 1 234
nb = 1 125
nb = 1 135
nb = 1 235
nb = 1 145
nb = 1 245
nb = 1 345
nb = 1 126
nb = 1 136
nb = 1 236
nb = 1 146
nb = 1 246
nb = 1 346
nb = 1 156
nb = 1 256
nb = 1 356
nb = 1 456
nb = 1 127
nb = 1 137
nb = 1 237
nb = 1 147
nb = 1 247
nb = 1 347
nb = 1 157
nb = 1 257
nb = 1 357
nb = 1 457
nb = 1 167
nb = 1 267
nb = 1 367
nb = 1 467
nb = 1 567
#(3,3) = 35
nb = 4 1234
nb = 4 1256
nb = 4 3456
nb = 4 1357
nb = 4 2457
nb = 4 2367
nb = 4 1467
nb = 1 1235
nb = 1 1245
nb = 1 1236
nb = 1 1246
nb = 1 1237
nb = 1 1347
nb = 1 1567
#(3,4) = 14
nb = 10 12345
nb = 9 12367
nb = 8 14567
nb = 4 23456
nb = 4 23457
#(3,5) = 5
nb = 20 123456
nb = 10 123457
nb = 4 123467
nb = 1 123567
#(3,6) = 4
nb = 35 1234567
#(3,7) = 1
nb = 1 1234
nb = 1 1235
nb = 1 1245
nb = 1 1345
nb = 1 2345
nb = 1 1236
nb = 1 1246
nb = 1 1346
nb = 1 2346
nb = 1 1256
nb = 1 1356
nb = 1 2356
nb = 1 1456
nb = 1 2456
nb = 1 3456
nb = 1 1237
nb = 1 1247
nb = 1 1347
nb = 1 2347
nb = 1 1257
nb = 1 1357
nb = 1 2357
nb = 1 1457
nb = 1 2457
nb = 1 3457
nb = 1 1267
nb = 1 1367
nb = 1 2367
nb = 1 1467
nb = 1 2467
nb = 1 3467
nb = 1 1567
nb = 1 2567
nb = 1 3567
nb = 1 4567
#(4,4) = 35
nb = 5 12345
nb = 5 12367
nb = 5 14567
nb = 4 23456
nb = 4 23457
nb = 3 12467
nb = 3 13467
nb = 3 12567
nb = 3 13567
#(4,5) = 9
nb = 15 123456
nb = 10 123457
nb = 6 123467
nb = 3 123567
nb = 1 124567
#(4,6) = 5
nb = 35 1234567
#(4,7) = 1
nb = 1 12345
nb = 1 12346
nb = 1 12356
nb = 1 12456
nb = 1 13456
nb = 1 23456
nb = 1 12347
nb = 1 12357
nb = 1 12457
nb = 1 13457
nb = 1 23457
nb = 1 12367
nb = 1 12467
nb = 1 13467
nb = 1 23467
nb = 1 12567
nb = 1 13567
nb = 1 23567
nb = 1 14567
nb = 1 24567
nb = 1 34567
#(5,5) = 21
nb = 6 123456
nb = 5 123457
nb = 4 123467
nb = 3 123567
nb = 2 124567
nb = 1 134567
#(5,6) = 6
nb = 21 1234567
#(5,7) = 1
nb = 1 123456
nb = 1 123457
nb = 1 123467
nb = 1 123567
nb = 1 124567
nb = 1 134567
nb = 1 234567
#(6,6) = 7
nb = 7 1234567
#(6,7) = 1
nb = 1 1234567
#(7,7) = 1
--
zwim.
Rien n'est impossible que la mesure de la volonté humaine...