CHAPTER 1. NUMBER SETS
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Figure 3.
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)^ ∩
19. _ y _ y ( ^ = _
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20. _ y ^ = _∩ ^′
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21. ^ y ^ = ∅
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22. ^ y _ = ^ =áÑ= ∩_ = ∅ .
^
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Figure 4.
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23. ( ^ _ ∩ ( ` = ` ) ^ ∩ y (_∩ ` )
) y
24. ^ = ′ y f ^
25. `~êíÉëá~å=mêçÇìÅí
}
` = ^× _ = ( { ) ó I ñ ñ ö ∈ ^ ~åÇ ó∈ _
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4