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Is there any rigorous definition for undefined?

Anonymous Sat 21 Aug 00:27:51 2021 No.13542245 View Reply Original Report

Quoted By: >>13542270

Say there is a function undefined on some points, strictly speaking, how exactly is the definition of such thing is written?

Anonymous

Anonymous Sat 21 Aug 2021 00:35:11 No.13542270 Report

Quoted By: >>13542347 >>13542356 >>13542364

>>13542245

Let $A\subseteq D$ and let $f:A\to B$ be a function on some points. We say that $c\in D$ is $\textrm{undefined}$ at $c$ if $c\notin A$ .

Anonymous

Anonymous Sat 21 Aug 2021 00:56:29 No.13542347 Report

Quoted By:

>>13542270
tf does B have to do with anything? Garbage proof. Into the trash it goes

Anonymous

Anonymous Sat 21 Aug 2021 00:57:56 No.13542356 Report

Quoted By:

>>13542270
>c is undefined at c

Anonymous

Anonymous Sat 21 Aug 2021 00:59:18 No.13542364 Report

Quoted By: >>13542403 >>13542442

>>13542270
Yes, but I'm asking for more accurate and 'smaller' scale definition for indefinability.
Let's say $\frac{1}{x}$ is undefinable for $x=0$, how exactly would you notate and understand that this is undefinable?

Anonymous

Anonymous Sat 21 Aug 2021 01:11:29 No.13542403 Report

Quoted By: >>13542440

>>13542364
>Let's say $\frac{1}{x}$ is undefinable for $x=0$
Why? I'll define f(0) to be 0.

OP of this thread

OP of this thread Sat 21 Aug 2021 01:28:16 No.13542440 Report

Quoted By:

>>13542403
I don't care, lol, maybe there is a misunderstanding.
Think about the history of the definition of limit, in the early history of infinitesimals there was not profound or rigorous definition like the delta-epsilon one, is the "indefinability" the same case?

Anonymous

Anonymous Sat 21 Aug 2021 01:28:30 No.13542442 Report

Quoted By: >>13542456

>>13542364
embarrassment of riches

1/0=u
--> 0*u=1

22/0=u
--> 0*u=22

OP of this thread

OP of this thread Sat 21 Aug 2021 01:33:05 No.13542456 Report

Quoted By:

>>13542442
Please exit this thread and contribute mathematics, I saw a social science thread somewhere on this board, might interest you

OP of this thread

OP of this thread Sat 21 Aug 2021 01:34:12 No.13542459 Report

Quoted By:

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