Báo cáo toán học: "Small Forbidden Configurations II" pptx

... chromatic number of the forbidden subgraph). Our results provide bounds that are remarkably accurate for small forbidden configurations but we still have some small forbidden configurations for which ... now imagine that exact bounds could be available for all 2 × l forbidden configurations. Some progress is reported for 3 × l forbidden configurations. These bounds are improvement...

Ngày tải lên: 07/08/2014, 06:22

... Griggs and Sali on small forbidden configurations. We define a matrix to be simple if it is a (0,1)-matrix with no repeated columns. Let F be a k ×l (0,1)-matrix (the forbidden configuration). Assume ... mine. References [1] R.P. Anstee, J.R. Griggs, A. Sali, Small Forbidden Configurations, Graphs and Com- binatorics 13(1997),97-118. [2] R.P. Anstee, Z. F¨uredi, Forbidden Submatrices, D...

Ngày tải lên: 07/08/2014, 15:23

... mixed [4, 5] 2 configurations. The polars of these configurations will be [7, 4] 2 configurations. 10.6 [5, 5], [5, 7], [7, 5] configurations Proposition 10.11. There are no astral [5, 5] 1 configurations. Proposition ... 2] astral configurations, it is easy to construct configurations, but they are rather uninteresting. Astral [4, 4] configurations are more constrained, but there are st...

Ngày tải lên: 07/08/2014, 08:20

... polar pairs of astral configurations to completely determine all movable configurations formed using two astral celestial configurations. Theorem 10. The only movable (n 4 ) configurations obtained ... j). By construction, the component configurations form a polar pair. These configurations account for half of the configurations from Family 2, and one quarter of the configurations fro...

Ngày tải lên: 07/08/2014, 13:21

... given m, how many distinct 5 -configurations C(m, (a, b; c, d), k, χ) are there? That is, are all the configurations different, for different k? 4. There are other h-astral configurations. Does this construction ... likely that they are as symmetric as possible. 1 2-astral configurations The construction of the 5 -configurations begins with astral 4 -configurations. Such a con- figuration, also...

Ngày tải lên: 08/08/2014, 11:20

Ngày tải lên: 07/08/2014, 05:23

... of forbidden minors. We obtain a characterization of such forbidden minors that can be written as clique k-sums for k =1, 2, 3. As a result we show constructively that the total number of forbidden ... properties of the forbidden minors. In particular, Section 2 shows that the known 57587 forbidden minors are internally 4-connected. Section 3 then naturally explores the possibility...

Ngày tải lên: 07/08/2014, 13:21

... GSQS(4 1 8 2 ) can be constructed using Theorem 21. Using Theorem 11 we can can construct all possible configurations of holes for GSQS of order 20, except types 1 2 8 1 10 1 and 2 1 8 1 10 1 which do not ... GSQS(2 1 4 3 8 1 ) and a GSQS(4 3 10 1 ). Then using Theorem 11 we can can construct all possible configurations of holes for GSQS of order 22, except when there are 2 holes of size 8...

Ngày tải lên: 07/08/2014, 15:23

Ngày tải lên: 07/08/2014, 21:21

Ngày tải lên: 05/08/2014, 15:20