#Subset of set intersection?

9 messages · Page 1 of 1 (latest)

wicked scarab
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is it true that $ C \subseteq (A \cap B) \implies C \subseteq A$ and $C \subseteq B$?

I know that $c \in A \cap B \implies c \in A$ and $c \in B$ by definition of set intersection, I was just wondering if there was an analogous proposition for subsets of intersections

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sage spear
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\left|C \right|\leq \left|A \cap B \right|\leq \left|A \right|

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This proves size for strict subset and since C is a subest of A intersect B, C is a subset of both A and subset fof B, therefore making it a strict subest of both

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wait it doesnt state that A and B are not the same set

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If A and B are not the same set then it holds true

wicked scarab
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$\left|C \right|\leq \left|A \cap B \right|\leq \left|A \right|$

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