Math Problem Statement

Analyze the mathematical statements about groups and determine which are correct, including properties of matrices, real numbers, and divisors.

Solution

From the uploaded image, the task is to identify correct mathematical statements about groups and group properties. Let’s analyze each statement:

  1. "Множество квадратных матриц второго порядка с определителем равным 1 является группой."

    • The set of 2×22 \times 2 matrices with determinant equal to 1 forms a group under matrix multiplication. This is true because:
      • Matrix multiplication is associative.
      • The determinant condition ensures the existence of an inverse matrix within the set.
      • The identity matrix (determinant = 1) is included in the set.
    • This statement is TRUE.
  2. "Множество квадратных матриц вида (ab0c)\begin{pmatrix} a & b \\ 0 & c \end{pmatrix}, a,b,cZa, b, c \in \mathbb{Z}" образуют группу относительно умножения матриц.

    • To verify if this forms a group under multiplication:
      • Closure: Multiplying two such matrices results in a matrix of the same form.
      • Associativity: Matrix multiplication is associative.
      • Identity: The identity matrix ((1001)\begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}) is not guaranteed unless specific constraints on a,b,ca, b, c exist.
      • Inverses: Not all matrices of this form have inverses in the integer domain Z\mathbb{Z}.
    • This statement is FALSE.
  3. "Множество действительных чисел на отрезке [-1, 1] с введенной операцией сложения является абелевой группой."

    • For the interval [1,1][-1, 1] under addition:
      • Closure: Adding two numbers from [1,1][-1, 1] may exceed the interval (e.g., 0.9+0.5=1.40.9 + 0.5 = 1.4).
      • Other group axioms fail due to the failure of closure.
    • This statement is FALSE.
  4. "Множество делителей числа 6 с введенной операцией умножения чисел является группой."

    • The divisors of 6 are {1,2,3,6}\{1, 2, 3, 6\}.
    • Closure: Multiplying two divisors results in another divisor of 6.
    • Associativity: Multiplication is associative.
    • Identity: The identity (1) exists.
    • Inverses: Not all divisors have inverses (e.g., 2×3=62 \times 3 = 6, but no inverse exists in this set for multiplication).
    • This statement is FALSE.

Summary of Correct Statements:

  • 1. TRUE
  • 2, 3, 4. FALSE

Would you like me to explain any specific step in more detail or provide further examples?

Related Questions:

  1. What are the conditions for a set to be considered a group?
  2. How does the determinant property relate to the invertibility of a matrix?
  3. Can you provide examples of other mathematical objects that form Abelian groups?
  4. Why does closure fail for the addition operation in bounded intervals like [1,1][-1, 1]?
  5. What are the key differences between Abelian and non-Abelian groups?

Tip:

When analyzing group properties, always start by checking closure and the existence of an identity, as these are often the quickest ways to determine if the set fails to be a group.

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Math Problem Analysis

Mathematical Concepts

Group Theory
Matrix Algebra
Number Theory
Set Theory

Formulas

Matrix multiplication rules
Group axioms: closure, associativity, identity, and inverses

Theorems

Properties of determinant in linear algebra
Definition of groups and Abelian groups

Suitable Grade Level

Undergraduate Mathematics