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Math Help - Need help understanding very basic set theory

  1. #1
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    Need help understanding very basic set theory

    Can someone please explain why:
    1) 3 E {1,2,3}
    2) 1 is not a subset of {1}
    3){2} is not a subset of {1,{2},{3}}
    4){1} is a subset of of {1,{2}}


    I kind of understand the basics but am still lost when it comes to knowing how to read these in my head and understand what going on....


    Thanks
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  2. #2
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    1) 3 E {1,2,3}
    2) 1 is not a subset of {1}
    3){2} is not a subset of {1,{2},{3}}
    4){1} is a subset of of {1,{2}}

    1. 3 is an element of the set
    2. 1 is not a subset of the set, just an element
    3. {2} is a subset of the set
    4. {1} is not a subset of the set,
    if the set were{{1},{2}} then {1} would be a subset of it
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  3. #3
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    Quote Originally Posted by statman101 View Post
    1) 3 E {1,2,3}
    2) 1 is not a subset of {1}
    3){2} is not a subset of {1,{2},{3}}
    4){1} is a subset of of {1,{2}}

    1. 3 is an element of the set
    2. 1 is not a subset of the set, just an element
    3. {2} is a subset of the set
    4. {1} is not a subset of the set,
    if the set were{{1},{2}} then {1} would be a subset of it
    statman101
    If I read you correctly, the you missed 3 & 4.
    \{2\}\not\subseteq\{1,\{2\},\{3\}\} but this is true \{2\}\in\{1,\{2\},\{3\}\}.

    \{1\}\subseteq\{1,\{2\},\{3\}\} because 1\in\{1,\{2\},\{3\}\}
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  4. #4
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    thanks for the reply guys
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