Math Problem Statement

Укажите все верные утверждения: 1. Любая подстановка раскладывается в произведение независимых циклов единственным образом. 2. ε(σ) = -ε(σ^{-1}). 3. Пусть дана подстановка σ и транспозиция τ, тогда ε(στ) = -ε(σ). 4. Подстановка — это биективное преобразование.

Solution

The image shows a question in Russian that translates to: "Indicate all correct statements," followed by four mathematical statements related to permutations. Here's a breakdown of the statements and their correctness:

  1. Любая подстановка раскладывается в произведение независимых циклов единственным образом
    Translation: "Any permutation can be decomposed into a product of independent cycles in a unique way."
    Correct: This is a fundamental property of permutations. Any permutation can be uniquely decomposed into disjoint cycles.

  2. ε(σ)=ε(σ1)\varepsilon(\sigma) = -\varepsilon(\sigma^{-1})
    Translation: "ε(σ)=ε(σ1)\varepsilon(\sigma) = -\varepsilon(\sigma^{-1})"
    Correct: This is true because the sign of a permutation (ε\varepsilon) changes for the inverse of the permutation.

  3. Пусть дана подстановка σ\sigma и транспозиция τ\tau, тогда ε(στ)=ε(σ)\varepsilon(\sigma\tau) = -\varepsilon(\sigma)
    Translation: "Let σ\sigma be a permutation and τ\tau a transposition, then ε(στ)=ε(σ)\varepsilon(\sigma\tau) = -\varepsilon(\sigma)"
    Correct: This is true. Multiplying a permutation by a transposition changes its sign because transpositions are odd permutations.

  4. Подстановка — это биективное преобразование
    Translation: "A permutation is a bijective transformation."
    Correct: This is true. By definition, a permutation is a bijection, meaning it is both injective and surjective.

Conclusion:

All four statements are correct.


Do you have any further questions or need more details on any of the concepts?

Here are 5 related questions:

  1. What is the cycle decomposition of a permutation?
  2. How does the sign of a permutation relate to its cycle structure?
  3. What is the formula for the number of transpositions in a permutation?
  4. Can every permutation be written as a product of transpositions?
  5. How does the inverse of a permutation affect its decomposition into cycles?

Tip: Remember that a transposition (a swap of two elements) is always an odd permutation!

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Math Problem Analysis

Mathematical Concepts

Permutations
Group Theory
Abstract Algebra

Formulas

Sign of a permutation (ε(σ))
Cycle decomposition
Transpositions in permutations

Theorems

Unique cycle decomposition theorem
Sign of a permutation
Properties of bijective transformations

Suitable Grade Level

Undergraduate