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ACEMockTest:Countable Set
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settheory&algebra
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Dec 24, 2016
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KISHALAY DAS
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Answer (A) and (B).
Subset of a countable set is countable. Set of all integers is countable and hence any subset of it is also countable.
Power set of a finite set is finite and hence countable.
answered
Dec 24, 2016
by
Samujjal Das
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comment
Thank you
I doubt about A. How do you map the subset to a number line of integers?
Enumeration method:
Go in incresing order of absolute value. In a particular absolute value, go in increasing order of the value.
Start from 0 >0.
Then 1 > 1,1
Then 2 > 2,2 and so on.
@GateSet
I think you meant
1,1 > 1
2,2 > 2
right?
Exactly
Thanks. Can you give me any good reference where the any ideas about how mappings are done is given?
As such I have no reference which I can give. I will try to find if there is any. Anyways, you an solve these type of questions intuitively.
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