sommese@nd.edu
A Maple 11 worksheet on Coloring Cubes: http://www.nd.edu/~sommese/math08S610/ColorCubes.mws
A Maple 11 worksheet for counting four vertex graphs: http://www.nd.edu/~sommese/math08S610/FourVertexGraphs.mws
A Maple 11 worksheet for the Petersen graph: http://www.nd.edu/~sommese/math08S610/PetersenGraph.mws
A) Draw the trees
with Prufer encodings
1234567
1111111
222
111333
B) Do a cyclic permutation
on the vertices of the graphs you have constructed, e.g.,
for the first tree above
(on the 9 vertices 1, 2, 3, 4, 5, 6, 7, 8, 9), replace 1 by 2,
2 by 3, etc. Now compute the Prufer encodings of
these permuted graphs.
C) What are the
degrees of the 36 vertices of the graph with Prufer encoding equal to 13 ones
followed by 12 twos followed
by 6 ones followed by 3 nines.
Compute the chromatic
polynomial for the graphs K_n with n from 1 to 5; and
for the graphs
K_{a,b} with
For the graphs K_n
with n from 3 to 8; for K_3 + K_5
joined at one point;
and for K_4+K_4 joined at one point,
a) write down the
adjacency matrices;
b) compute the number
of edges;
c) compute the number
of walks of length 4;
d) compute the number
of triangles;
e) compute the ranks
of the adjacency matrices;
f) compute the
eigenvalues of the matrices; and
g) compute the
diameters of the graphs.
Given a poset P = (X,
R) with |X| = n > 0; we have shown there is at least one
order-preserving map
to a chain of length n. For each of
the posets P on page 188,
use the zeta
functions of their associated lattices L(P) to compute the numbers of
these order
preserving maps.
Problems 1 and 8 of
12.10.
Problems 8 of 7.5.
Problems 1 (only for
faces and for edges), 2 of 15.8.
Problems 2, 3, 6, and
7 of 13.6.
A) Write the permutation in
cycle notation. This gives a
partition of 8.
B) How many different permutations give rise to the same partition?
Problems 15b, 16 of 4.8.
Do Problems 7 and 8 of 5.6.
Compute S(n,k)
directly for k greater than n - 3 and also for k less than 3.
Do Problems 14, 17 of
4.8.
Do Problems 3, 8, 10,
11 of 2.8.
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