In a deposition submitted under oath, William Elliot said:
BS> Infinities are strange. Yes, you can have infinite sets of
BS> different sizes, but that is not always what is implied when I say
BS> w + w = w (where I use w to be the lowercase omega as a symbol for
BS> any particular but arbitrarily chosen infinite set) or w ^ 2 = w.
BS> Using the same symbol implies the same set.
WE> This is questionable notation. as lower case omega is used for the
WE> ordinal number of the integers in ascending order. I suggest capital
WE> letters infinity such as A, B for aleph, beth as in A0 aleph null or
WE> denumerable infinity. It is true that for A or B infinite, A + B = A
WE> * B = max(A,B) while for A B
I saw this notation in a book _Infinity and the Mind_ by Rudy
Rucker. I adopted it here because I can't find the infinity key on my
keyboard. ;^) But I'll go with A(0) for aleph-null, etc.
BS> One-to-one (OTO): a function is OTO if, and only if, every x
BS> plugged into the function results in a unique y. IOW, if f(x1) =
BS> f(x2) then x1 = x2. The function x^3 is an example of a function
BS> which is OTO. Every x in the domain leads to a unique y in the range
BS> of the function. There may be some y's without corresponding x's, but
BS> no x's without corresponding y's.
WE> A 1-1 function is an invertible function, a bijection.
Well, try injective. A bijection is a 1-1 correspondence.
BS> ONTO: a function is ONTO if, and only if, every element y in the
BS> range of the function has an x in the domain that takes the function
BS> to that y. IOW, for every y, there exists an x such that y = f(x).
BS> There may be some x's without corresponding y's, and some x's may lead
BS> to the same y, but no y's without corresponding x's.
WE> This is a weak definition.
Yes, perhaps because I wanted to make this clear to anyone not
familiar with mathematical notation and proofs, hence tried to simplify
it. Had I wanted to be as precise as possible, I would have defined
a function F:X->Y as ONTO (or surjective) iff for every y in the set Y,
there exists an x in the set X | F(x) = y.
BS> A set is countably infinite if, and only if, it has the same
BS> cardinality as the set of positive integers Z+. A set is countable
BS> if, and only if, it is finite or countable infinite. A set that is
BS> not countable is called uncountable.
WE> I use the word denumerable to mean countably infinite.
Okay. I'll try and remember that.
BS> One must understand the above to make sense of the rest of my proofs,
WE> Learned this stuff while still in high school.
I've just been learning it the last year or so in college.
... And smale foweles maken melodye that slepen al the nyght with open eye.
--- PPoint 2.05
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* Origin: Seven Wells On-Line * Nashville, TN (1:116/30.3)
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