24. Find the mistake in the "proof" of the following "proposition." Is this "proposition true? If not, find a counterexample. "Proposition." Let A, B and C be sets and suppose that ACBỤC Then A s Bor ACC. "proof" Let x be any object and suppose that xEA. ThenxEBUC since ACBUC Thus, by the definition of union, xE Bor xe C. Therefore, for all objects x, ifEA, then xe Bor, for all objects x, if xEA, then xEC. Hence, by the definition of subset, AC Bor ACC.

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### Proposition Analysis

**Problem:**
Examine the provided "proof" of the given "proposition." Is this "proposition" true? If not, identify a counterexample.

#### Proposition
Consider sets \( A \), \( B \), and \( C \) such that \( A \subseteq B \cup C \). This implies \( A \subseteq B \) or \( A \subseteq C \).

#### Provided Proof
To prove or disprove the proposition, follow these steps:

1. **Assumption:**
   Let \( x \) be any arbitrary object and suppose \( x \in A \).
   
2. **Implication:**
   Since \( A \subseteq B \cup C \), it implies \( x \in B \cup C \).
   
3. **Definition of Union:**
   By the definition of the union, \( x \in B \) or \( x \in C \).

4. **Conclusion:**
   Therefore, for any object \( x \), if \( x \in A \), then \( x \in B \) or \( x \in C \).

5. **Subset Definition:**
   Hence, by the definition of a subset, we can conclude \( A \subseteq B \) or \( A \subseteq C \).

#### Analysis and Error Identification

The provided "proof" contains a flaw. It incorrectly assumes that if \( x \) belongs to the union \( B \cup C \), then \( x \) necessarily belongs to either \( B \) or \( C \) independently for all elements in \( A \). However, there could be elements of \( A \) that belong to \( B \cup C \) but not entirely to one set \( B \) or \( C \).

#### Counterexample

Consider the following sets:
- \( A = \{1, 2\} \)
- \( B = \{1\} \)
- \( C = \{2\} \)

Here, \( A \subseteq B \cup C \) because every element of \( A \) is in the union of \( B \) and \( C \):
\[ A = \{1, 2\} \text{ and } B \cup C = \{1, 2\} \]

However, \( A \) is not a subset of \( B \) (since \(
Transcribed Image Text:### Proposition Analysis **Problem:** Examine the provided "proof" of the given "proposition." Is this "proposition" true? If not, identify a counterexample. #### Proposition Consider sets \( A \), \( B \), and \( C \) such that \( A \subseteq B \cup C \). This implies \( A \subseteq B \) or \( A \subseteq C \). #### Provided Proof To prove or disprove the proposition, follow these steps: 1. **Assumption:** Let \( x \) be any arbitrary object and suppose \( x \in A \). 2. **Implication:** Since \( A \subseteq B \cup C \), it implies \( x \in B \cup C \). 3. **Definition of Union:** By the definition of the union, \( x \in B \) or \( x \in C \). 4. **Conclusion:** Therefore, for any object \( x \), if \( x \in A \), then \( x \in B \) or \( x \in C \). 5. **Subset Definition:** Hence, by the definition of a subset, we can conclude \( A \subseteq B \) or \( A \subseteq C \). #### Analysis and Error Identification The provided "proof" contains a flaw. It incorrectly assumes that if \( x \) belongs to the union \( B \cup C \), then \( x \) necessarily belongs to either \( B \) or \( C \) independently for all elements in \( A \). However, there could be elements of \( A \) that belong to \( B \cup C \) but not entirely to one set \( B \) or \( C \). #### Counterexample Consider the following sets: - \( A = \{1, 2\} \) - \( B = \{1\} \) - \( C = \{2\} \) Here, \( A \subseteq B \cup C \) because every element of \( A \) is in the union of \( B \) and \( C \): \[ A = \{1, 2\} \text{ and } B \cup C = \{1, 2\} \] However, \( A \) is not a subset of \( B \) (since \(
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