Can Simplification Prove (A I B) Subset of A using Special Notation?

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SUMMARY

The discussion centers on proving that the intersection of two sets, denoted as (A ∩ B), is a subset of A using simplification from the rule of inference. It is established that the logical rule applies to logical statements rather than directly to sets. The correct approach involves decomposing the statement into logical components, starting with the assumption that x belongs to A ∩ B, leading to the conclusion that x must belong to A.

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  • Understanding of set theory, specifically set operations like intersection.
  • Familiarity with logical statements and rules of inference.
  • Knowledge of notation used in mathematical logic.
  • Ability to manipulate and decompose logical expressions.
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  • Study the properties of set operations, particularly intersection and subset relations.
  • Learn about logical inference rules and their applications in mathematical proofs.
  • Explore examples of set proofs using logical decomposition techniques.
  • Review notation conventions in set theory and mathematical logic.
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Mathematicians, students of discrete mathematics, and anyone interested in understanding set theory and logical proofs will benefit from this discussion.

brad sue
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Hi,

with my special notation:
I- intersection

Can we prove that:
(A I B) subset of A by simplification from the rule of inference

since A I B -->A ??

If not, please can I have some suggestions?
B
 
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brad sue said:
Hi,

with my special notation:
I- intersection

Can we prove that:
(A I B) subset of A by simplification from the rule of inference

since A I B -->A ??

If not, please can I have some suggestions?
B
Sort of--that logical rule applies only to logical statements, not directly to sets. It says that you can conclude X from the statement X AND Y. The standard way to prove that [tex]A \cap B \subseteq A[/tex] starts by decomposing it into logical statements.
Assume [tex]x \in A \cap B[/tex]
Then [tex](x \in A) \vee (x \in B)[/tex]
You can finish it
 
0rthodontist said:
Sort of--that logical rule applies only to logical statements, not directly to sets. It says that you can conclude X from the statement X AND Y. The standard way to prove that [tex]A \cap B \subseteq A[/tex] starts by decomposing it into logical statements.
Assume [tex]x \in A \cap B[/tex]
Then [tex](x \in A) \vee (x \in B)[/tex]
You can finish it

OK I understand what to do.
Thank you
 

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