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Let σ=(134), τ=(23)(145), ρ=(56)(78), and α=(12)(145) in S8. Compute the following.
στ
τσ
τ2
τ−1
o(τ)
o(ρ)
o(α)
⟨τ⟩
Throughout, write all permutations using disjoint cycle notation, and write all dihedral group elements in standard form.
Let σ=(134), τ=(23)(145), ρ=(56)(78), and α=(12)(145) in S8. Compute the following.
στ
τσ
τ2
τ−1
o(τ)
o(ρ)
o(α)
⟨τ⟩
Prove Lemma 6.3.4.
Prove that An is a subgroup of Sn.
Prove or disprove: The set of all odd permutations in Sn is a subgroup of Sn.
Let n be an integer greater than 2. m∈{1,2,…,n}, and let H={σ∈Sn:σ(m)=m} (in other words, H is the set of all permutations in Sn that fix m).
Prove that H≤Sn.
Identify a familiar group to which H is isomorphic. (You do not need to show any work.)
Write rfr2frfr in D5 in standard form.
Prove or disprove: D6≃S6.
Which elements of D4 (if any)
have order 2?
have order 3?
Let n be an even integer that's greater than or equal to 4. Prove that rn/2∈Z(Dn): that is, prove that rn/2 commutes with every element of Dn. (Do NOT simply refer to the last statement in Theorem 6.5.10; that is the statement you are proving here.)