Bravo Thunderbird!
On 07 Jun 2009, at 18:39, m.a. wrote:
>
>> Bruno et. al.,
>> Good news! I have discovered that the math
>> symbols copy faithfully here in my Thunderbird email. Henceforth, I
>> will open all list letters here. Please refresh my memory for the
>> following symbols:
>>
>>
>> 1. The ∅ is called___THE EMPTY SET_____and means______THE SET
>> WITH NO ELEMENTS
The empty set described in extension: { }
The empty set described in intension. Well, let me think. The set of
french which are bigger than 42 km tall.
A cynical definition would be: the set of honest politicians.
A mathematical one: the set of x such that x is different from x.
It is just the set which has no elements. It is empty.
>>
>> 2. The ∪ is called________UNION______and means: A ∪ B__= {x
>> such-that x belongs to A or x belongs to B};
>> A u B is the set obtained by doing the union of A and B.
>> 3. The ∩ is called_____INTERSECTION____and means__A ∩ B__=
>> {x such-that x belongs to A andr x belongs to B}; A u B is the
>> set obtained by doing the intersection of A and B. It is the set of
>> elements which are in both A and B._
Examples:
{1, 2, 3} ∩ {2, 4, 3} = {2, 3}
{1, 2, 3} u {2, 4, 3} = {1, 2, 3, 4}
{1, 2, 3} ∩ {4, 5, 6} = ∅
{1, 2, 3} u {4, 5, 6} = {1, 2, 3, 4, 5, 6}
OK?
Bruno
>>
>>
>> ----- Original Message -----
>> From: Bruno Marchal
>> To: everything-list.domain.name.hidden
>> Sent: Wednesday, June 03, 2009 1:15 PM
>> Subject: Re: The seven step-Mathematical preliminaries 2
>>
>>
>> ∅ ∪ A =
>> ∅ ∪ B =
>> A ∪ ∅ =
>> B ∪ ∅ =
>> N ∩ ∅ =
>> B ∩ ∅ =
>> ∅ ∩ B =
>> ∅ ∩ ∅ =
>> ∅ ∪ ∅ =
>>
>>
>>
>>
>
> >
http://iridia.ulb.ac.be/~marchal/
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "Everything List" group.
To post to this group, send email to everything-list.domain.name.hidden
To unsubscribe from this group, send email to everything-list+unsubscribe.domain.name.hidden
For more options, visit this group at
http://groups.google.com/group/everything-list?hl=en
-~----------~----~----~----~------~----~------~--~---
Received on Sun Jun 07 2009 - 20:57:54 PDT