Group of Symmetries of a Cube
a. Carefully describe the group of symmetries of a cube.
Describe the types, the orders, and the structures of the groups
and their elements. After clearly naming the elements in some way,
provide tables for each group. Describe them as a group of
permutations on the vertices.
b. Next, carefully describe each of these groups as subgroups of
some permutation group. Be sure to provide reasons for your
choices.
c. What are the POSSIBLE...
Find two distinct subgroups of order 2 of the group D3 of
symmetries of an equilateral triangle. Explain why this fact alone
shows that D3 is not a cynic group.
SupposeG=〈a〉is a cyclic group of order 12.
Find all of the proper subgroups of G, and list their elements.
Find all the generators of each subgroup. Explain your
reasoning.
Consider the group Z/24Z.
(a) Find the subgroups 〈21〉 and 〈10〉.
(b) Find all generators for the subgroup 〈21〉 ∩ 〈10〉.
(c) In general, what is a generator for 〈a〉 ∩ 〈b〉 in Z/nZ? Prove
your assertion.
Group of Symmetries of a Rectangle
a. Carefully describe the group of symmetries of a rectangle
Describe the types, the orders, and the structures of the groups
and their elements. After clearly naming the elements in some way,
provide tables for each group. Describe them as a group of
permutations on the vertices.
b. Next, carefully describe each of these groups as subgroups of
some permutation group. Be sure to provide reasons for your
choices.
c. What are the POSSIBLE...
Let D8 be the group of symmetries of the square.
(a) Show that D8 can be generated by the rotation through 90◦
and any one of the four reflections.
(b) Show that D8 can be generated by two reflections.
(c) Is it true that any choice of a pair of (distinct) reflections
is a generating set of D8?
Note: What is mainly required here is patience. The first
important step is to set up your notation in a clear way,...
(a) Show that a group that has only a finite number of subgroups
must be a finite group.
(b) Let G be a group that has exactly one nontrivial, proper
subgroup. Show that G must be isomorphic to Zp2 for some prime
number p. (Hint: use part (a) to conclude that G is finite. Let
H
be the one nontrivial, proper subgroup of G. Start by showing
that G and hence H must be cyclic.)
Find the symmetries of the Platonic Solids: Cube, Tetrahedron,
Octahedron, Icosahedron, and Dodecahedron.
I. You need to describe with words the planes of reflectional
symmetry and identify how many there are in any of the categories
found.
II You need to describe with words the axes(lines) of rotational
symmetry. For each type of axis, determine how many there are and
the order of rotation.
(1) Let G be a group and H, K be subgroups of G.
(a) Show that if H is a normal subgroup, then HK = {xy|x ? H, y ?
K} is a
subgroup of G.
(b) Show that if H and K are both normal subgroups, then HK is also
a normal
subgroup.
(c) Give an example of subgroups H and K such that HK is not a
subgroup of G.
***PLEASE SHOW ALL STEPS WITH EXPLANATIONS***
Let G be a group (not necessarily an Abelian group) of
order 425. Prove that G must have an element of order
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