1
Examples 14.1–14.5 in the first section each describe an action of a group on a set which will give rise to the equivalence relation defined by -equivalence. For each example, compute the equivalence classes of the equivalence relation, the -.
Important: to view this notebook properly you will need to execute the cell above, which assumes you have an Internet connection. It should already be selected, or place your cursor anywhere above to select. Then press the "Run" button in the menu bar above (the right-pointing arrowhead), or press Shift-Enter on your keyboard.
ParseError: KaTeX parse error: \newcommand{\lt} attempting to redefine \lt; use \renewcommand
Compute all and all for each of the following permutation groups.
(a)
Let be the additive group of real numbers. Let the action of on the real plane be given by rotating the plane counterclockwise about the origin through radians. Let be a point on the plane other than the origin.
Show that is a -set.
Describe geometrically the orbit containing
Find the group
Let and suppose that acts on itself by conjugation; that is,
Determine the conjugacy classes (orbits) of each element of
Determine all of the isotropy subgroups for each element of
Find the conjugacy classes and the class equation for each of the following groups.
The conjugacy classes for are
The class equation is
Write the class equation for and for
If a square remains fixed in the plane, how many different ways can the corners of the square be colored if three colors are used?
How many ways can the vertices of an equilateral triangle be colored using three different colors?
Find the number of ways a six-sided die can be constructed if each side is marked differently with dots.
Up to a rotation, how many ways can the faces of a cube be colored with three different colors?
The group of rigid motions of the cube can be described by the allowable permutations of the six faces and is isomorphic to There are the identity cycle, 6 permutations with the structure that correspond to the quarter turns, 3 permutations with the structure that correspond to the half turns, 6 permutations with the structure that correspond to rotating the cube about the centers of opposite edges, and 8 permutations with the structure that correspond to rotating the cube about opposite vertices.
Consider 12 straight wires of equal lengths with their ends soldered together to form the edges of a cube. Either silver or copper wire can be used for each edge. How many different ways can the cube be constructed?
Suppose that we color each of the eight corners of a cube. Using three different colors, how many ways can the corners be colored up to a rotation of the cube?
Each of the faces of a regular tetrahedron can be painted either red or white. Up to a rotation, how many different ways can the tetrahedron be painted?
Suppose that the vertices of a regular hexagon are to be colored either red or white. How many ways can this be done up to a symmetry of the hexagon?
A molecule of benzene is made up of six carbon atoms and six hydrogen atoms, linked together in a hexagonal shape as in Figure 14.28.
How many different compounds can be formed by replacing one or more of the hydrogen atoms with a chlorine atom?
Find the number of different chemical compounds that can be formed by replacing three of the six hydrogen atoms in a benzene ring with a radical.
How many equivalence classes of switching functions are there if the input variables and can be permuted by any permutation in What if the input variables and can be permuted by any permutation in
How many equivalence classes of switching functions are there if the input variables and can be permuted by any permutation in the subgroup of generated by the permutation
A striped necktie has 12 bands of color. Each band can be colored by one of four possible colors. How many possible different-colored neckties are there?
A group acts on a -set if the identity is the only element of that leaves every element of fixed. Show that acts faithfully on if and only if no two distinct elements of have the same action on each element of
Let be prime. Show that the number of different abelian groups of order (up to isomorphism) is the same as the number of conjugacy classes in
Let Show that for any
Use the fact that if and only if
Let be a nonabelian group for prime. Prove that
Let be a group with order where is prime and a finite -set. If is the set of elements in fixed by the group action, then prove that
If is a group of order where is prime and show that must have a proper subgroup of order If is it true that will have a proper subgroup of order