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Topic: Matheology S 224
Replies: 16   Last Post: Apr 21, 2013 6:53 PM

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namducnguyen

Posts: 2,688
Registered: 12/13/04
Re: Matheology S 224
Posted: Apr 20, 2013 11:10 AM
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On 20/04/2013 4:47 AM, Frederick Williams wrote:
> Alan Smaill wrote:
>>
>> Frederick Williams <freddywilliams@btinternet.com> writes:
>>

>>> Nam Nguyen wrote:
>>>>
>>>> On 19/04/2013 5:55 AM, Frederick Williams wrote:

>>>>> Nam Nguyen wrote:
>>>>>>
>>>>>> On 18/04/2013 7:19 AM, Frederick Williams wrote:

>>>
>>>>
>>>>>
>>>>>>> Also, as I remarked elsewhere, "x e S' /\ Ay[ y e S' -> y e S]" doesn't
>>>>>>> express "x is in a non-empty subset of S".

>>>>>>
>>>>>> Why?

>>>>>
>>>>> It says that x is in S' and S' is a subset of S.

>>>>
>>>> How does that contradict that it would express "x is in a non-empty
>>>> subset of S", in this context where we'd borrow the expressibility
>>>> of L(ZF) as much as we could, as I had alluded before?

>>>
>>> You really are plumbing the depths. To express that x is non-empty you
>>> have to say that something is in x, not that x is in something.

>>
>> but the claim was that x *is in* a non-empty set --
>> in this case S', which is non-empty, since x is an element of S',
>> and S' is a subset of S.

>
> Oh, I am so sorry, I did not see the "in" in "x is in a non-empty subset
> of S", and it seems I didn't see it three or four times. My apologies
> to Nam.


Np. Typo, overlook do happen from time to time!

>
>> (Much though it would be good for Nam to realise that
>> some background set theory axioms would be kind of useful here)

>


--
----------------------------------------------------
There is no remainder in the mathematics of infinity.

NYOGEN SENZAKI
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