Math Problem Statement

Can ${0,1}$ be a field for some operations of addition and multiplication? Justify.

Solution

Yes, the set {0,1}\{0, 1\} can indeed be a field under specific definitions of addition and multiplication. A field is a set equipped with two operations, addition and multiplication, satisfying the following properties:

  1. Closure: The set is closed under addition and multiplication.
  2. Associativity: Both addition and multiplication are associative.
  3. Commutativity: Both addition and multiplication are commutative.
  4. Identity Elements: There are additive (00) and multiplicative (11) identities.
  5. Inverses: Every element has an additive inverse (opposite) and every non-zero element has a multiplicative inverse (reciprocal).
  6. Distributivity: Multiplication distributes over addition.

Defining Addition and Multiplication

To form a field with {0,1}\{0, 1\}, we can define addition and multiplication as follows:

  • Addition (++) is defined as: + & 0 & 1 \\ \hline 0 & 0 & 1 \\ 1 & 1 & 0 \\ \end{array}$$
  • Multiplication (\cdot) is defined as: \cdot & 0 & 1 \\ \hline 0 & 0 & 0 \\ 1 & 0 & 1 \\ \end{array}$$

Checking Field Axioms

  1. Closure:

    • Addition and multiplication of any two elements in {0,1}\{0, 1\} result in elements still in {0,1}\{0, 1\}.
  2. Associativity:

    • Addition: (0+0)+1=0+1=1(0 + 0) + 1 = 0 + 1 = 1 and 0+(0+1)=0+1=10 + (0 + 1) = 0 + 1 = 1, etc., for all combinations.
    • Multiplication: (00)1=01=0(0 \cdot 0) \cdot 1 = 0 \cdot 1 = 0 and 0(01)=01=00 \cdot (0 \cdot 1) = 0 \cdot 1 = 0, etc., for all combinations.
  3. Commutativity:

    • Both addition and multiplication are symmetric, so they are commutative.
  4. Identity Elements:

    • Additive identity: 00, since 0+x=x+0=x0 + x = x + 0 = x for any x{0,1}x \in \{0, 1\}.
    • Multiplicative identity: 11, since 1x=x1=x1 \cdot x = x \cdot 1 = x for any x{0,1}x \in \{0, 1\}.
  5. Inverses:

    • Additive inverses: 00 is its own inverse (0+0=00 + 0 = 0), and 11 is its own inverse (1+1=01 + 1 = 0).
    • Multiplicative inverses: 11 is its own inverse (11=11 \cdot 1 = 1), and 00 has no multiplicative inverse, which is allowed since it's the only element that does not need a multiplicative inverse.
  6. Distributivity:

    • Multiplication distributes over addition, as shown by all possible combinations, e.g., 1(0+1)=11=11 \cdot (0 + 1) = 1 \cdot 1 = 1 and (10)+(11)=0+1=1(1 \cdot 0) + (1 \cdot 1) = 0 + 1 = 1, etc.

Conclusion

The set {0,1}\{0, 1\} with these definitions of addition and multiplication satisfies all the field axioms. This structure is known as the finite field of two elements, often denoted by F2\mathbb{F}_2 or Z/2Z\mathbb{Z}/2\mathbb{Z}. It is the simplest example of a finite field and has wide applications in areas like coding theory, cryptography, and algebra.

Would you like more details on any particular property or aspect of this field? Here are some related questions:

  1. How does the field F2\mathbb{F}_2 differ from other finite fields?
  2. What are the applications of the field F2\mathbb{F}_2 in computer science?
  3. Can a set with more than two elements form a field with similar operations?
  4. How are addition and multiplication defined in larger finite fields?
  5. What is the significance of characteristic 2 fields in algebra?

Tip: Finite fields, especially F2\mathbb{F}_2, are fundamental in digital systems due to their simplicity and ease of implementation in binary operations.

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Math Problem Analysis

Mathematical Concepts

Field Theory
Abstract Algebra
Finite Fields

Formulas

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Theorems

Field Axioms
Finite Fields Theory

Suitable Grade Level

Undergraduate