Groups and Subgroups
This quiz covers fundamental concepts and properties related to groups and subgroups in abstract algebra.
Questions
Let G be a group and H a subset of G. Which of the following conditions is necessary for H to be a subgroup of G?
- H is non-empty.
- H is closed under the group operation.
- H contains the identity element of G.
- All of the above.
If H is a subgroup of a group G, then the order of H (|H|) is:
- Always a factor of the order of G (|G|).
- Always less than or equal to the order of G (|G|).
- Always greater than or equal to the order of G (|G|).
- None of the above.
Which of the following is NOT a necessary condition for a subset H of a group G to be a subgroup?
- H is non-empty.
- H is closed under the group operation.
- H contains the identity element of G.
- H contains the inverse of every element in H.
The intersection of two subgroups of a group G is:
- Always a subgroup of G.
- Sometimes a subgroup of G.
- Never a subgroup of G.
- None of the above.
The union of two subgroups of a group G is:
- Always a subgroup of G.
- Sometimes a subgroup of G.
- Never a subgroup of G.
- None of the above.
Let G be a group and H a subgroup of G. The set of all left cosets of H in G is denoted by:
- G/H
- H/G
- G\H
- H\G
Let G be a group and H a subgroup of G. The set of all right cosets of H in G is denoted by:
- G/H
- H/G
- G\H
- H\G
If H is a subgroup of a group G, then the index of H in G (|G:H|) is:
- The number of elements in H.
- The number of elements in G.
- The number of cosets of H in G.
- None of the above.
Let G be a group and H a subgroup of G. The normalizer of H in G, denoted by $N_G(H)$, is:
- The set of all elements in G that commute with every element in H.
- The set of all elements in G that conjugate H.
- The set of all elements in G that are contained in some conjugate of H.
- All of the above.
Let G be a group and H a subgroup of G. The centralizer of H in G, denoted by $C_G(H)$, is:
- The set of all elements in G that commute with every element in H.
- The set of all elements in G that conjugate H.
- The set of all elements in G that are contained in some conjugate of H.
- None of the above.
A group G is called abelian if:
- Every element in G has order 2.
- Every element in G commutes with every other element in G.
- Every subgroup of G is normal.
- None of the above.
A group G is called cyclic if:
- It is generated by a single element.
- It is abelian.
- It is finite.
- None of the above.
The order of an element a in a group G is:
- The smallest positive integer n such that $a^n = e$, where e is the identity element of G.
- The largest positive integer n such that $a^n = e$, where e is the identity element of G.
- The number of elements in the cyclic subgroup generated by a.
- None of the above.
Let G be a group and H a subgroup of G. If the order of H is p, where p is a prime number, then:
- H is a normal subgroup of G.
- H is a cyclic subgroup of G.
- Every element in H has order p.
- All of the above.
The Sylow theorems provide information about:
- The existence and number of subgroups of a given order in a finite group.
- The structure of finite groups.
- The solvability of groups.
- None of the above.