matroid theory
san francisco state university
universidad de los andes
federico ardila
2007

parcial 1 y soluciones.
parcial 2 y soluciones.

hw 1 due 2/2/07 in sf, 2/5/07 in bog.
hw 2 due 2/16/07 in sf, 2/19/07 in bog.
hw 3 due 3/02/07 in sf, 3/05/07 in bog.
hw 4 due 3/19/07 in sf, 3/21/07 in bog.
hw 5 due 4/02/07 in sf, 3/30/07 in bog.

hw 1

1 (chris o'neill) 1 (alex fink) 1 (andres uribe)
2 (jeff doker)
3a 3b (kim seashore)
4a 4b (anna brown)
5 (alex fink)
6a 6b (amanda ruiz) 6a 6b (mariana laverde) 6 (santiago saavedra)

hw 2

1a, 1b (anna brown)
2a 2b 2c 2d 2e (alex fink), 2(b) 2(c)a 2(c)b (amanda ruiz), 2(b) (cesar ceballos)
3 (miranda wang)
4a 4b (kim seashore)
5 (jeff doker)
6 (alex fink)

hw 3

1a, 1b (anna brown)
2 (cesar ceballos)
3 (laura escobar) 3 (alex fink)
4 (andres uribe)
5 (cesar ceballos)
6 (alex fink), 6 (federico ardila and sara billey - from this paper. theorem 6.2 describes more explicitly what "good sets of holes" look like.)

hw 4

1 (anna brown)
2 (jeff doker)
3 (amanda ruiz)
4 (santiago saavedra)
5 (cesar ceballos)
note. several students in sf produced this very nice proof of problem 4, which is complete except for this lemma.

hw 5

1 (cesar ceballos)
2 (laura escobar)
4 (carolina benedetti)
5a (jeff doker)
5b (chris o'neill)
5 (alex fink)
note. i labelled problem 2 "representability over a field of characteristic zero has infinitely many forbidden minors." felipe rincon pointed out that 2a. and 2b are not enough to conclude that. he came up with this beautiful argument to complete the proof of that statement.