doughnut, coffee cup, scissors, pretzel, ...
 

That might explain it, I guess. So if I see something before me that I
am inclined to refer to as a "coffee cup", how am I to tell whether or
not it actually _is_ a coffee cup in some essential way?

In fact, it could be your doughnut.

(Old topology joke.)

My doughnuts are generally not continuously deformable to coffee cups.
I'd have to poke them with a stick to make that true, and that would
squirt jam everywhere.

doughnut, coffee cup, scissors, pretzel, ...
 

Jonathan de Boyne Pollard wrote:
That might explain it, I guess. So if I see something before me that I
am inclined to refer to as a "coffee cup", how am I to tell whether or
not it actually _is_ a coffee cup in some essential way?

In fact, it could be your doughnut.

(Old topology joke.)

My doughnuts are generally not continuously deformable to coffee cups.
I'd have to poke them with a stick to make that true, and that would
squirt jam everywhere.

Would topology have still been the field it is today if doughnuts had
not existed?

--
Peter Moylan, Newcastle, NSW, Australia. http://www.pmoylan.org
For an e-mail address, see my web page.

doughnut, coffee cup, scissors, pretzel, ...
 

On 26/08/11 7:36 AM, Peter Moylan wrote:
Jonathan de Boyne Pollard wrote:
That might explain it, I guess. So if I see something before me that I
am inclined to refer to as a "coffee cup", how am I to tell whether or
not it actually _is_ a coffee cup in some essential way?

In fact, it could be your doughnut.

(Old topology joke.)

My doughnuts are generally not continuously deformable to coffee cups.
I'd have to poke them with a stick to make that true, and that would
squirt jam everywhere.

Would topology have still been the field it is today if doughnuts had
not existed?


But when I was a child in England, doughnuts were amorphous lumps and
were definitely not ring-shaped and had no visible hole. It took me a
while before I understood what Americans writers were talking about when
they said "donut-shaped". I don't think I saw a toroidal doughnut until
I was in my twenties.

--
Robert Bannister

doughnut, coffee cup, scissors, pretzel, ...
 

"Peter Moylan" wrote in message
. au...
Jonathan de Boyne Pollard wrote:
That might explain it, I guess. So if I see something before me that I
am inclined to refer to as a "coffee cup", how am I to tell whether or
not it actually _is_ a coffee cup in some essential way?

In fact, it could be your doughnut.

(Old topology joke.)

My doughnuts are generally not continuously deformable to coffee cups.
I'd have to poke them with a stick to make that true, and that would
squirt jam everywhere.

Would topology have still been the field it is today if doughnuts had
not existed?

All topology textbooks would contain pictures of coffee cups.

Or topologically identical people?

pjk

Why coffee mug is ingested in this conversation. I didn’t’ get it !......

Actually it's in the title of this thread: "doughnut, coffee cup, scissors, pretzel, ..."