Topology

Does anyone know how many holes the human body has, topologically speaking? I think the answer is 3. Anyone get a different answer? Meet me at this thread in 15 minutes and we'll wrestle until one of us is right.

Originally posted by PBE6
Does anyone know how many holes the human body has, topologically speaking? I think the answer is 3. Anyone get a different answer? Meet me at this thread in 15 minutes and we'll wrestle until one of us is right.

AFAIK the human body (viewed at a sufficiently macroscopic level) is a solid torus, but I'd be interested to see your description.

Originally posted by Acolyte
AFAIK the human body (viewed at a sufficiently macroscopic level) is a solid torus, but I'd be interested to see your description.

I was thinking of the glory tube, of course, but also the two nose holes. Do they count?

Originally posted by PBE6
I was thinking of the glory tube, of course, but also the two nose holes. Do they count?

Wait, if they count then I guess the ears do as well because they're all connected. So I guess my answer is 5.

For men or women?
Men have 10 holes in their body, and women have 13.

The ears are not holes...the eardrum shuts the outside world off from the inside of your head.

Originally posted by TheMaster37
The ears are not holes...the eardrum shuts the outside world off from the inside of your head.

What's a "hole"?

There are, depending on gender: urethra, nostrils, ears, mouth, anus, eyes, pores, nipples, vagina.

Originally posted by yevgenip
For men or women?
Men have 10 holes in their body, and women have 13.

OK, I have used only 9 fingers to fill (or cover) them all - one finger left. Maybe I cannot count, or am genetically incomplete?

List them please?

Originally posted by TheMaster37
The ears are not holes...the eardrum shuts the outside world off from the inside of your head.

They're connected to your throat. That's why you have ear, nose and throat specialists.

OK, so what makes a hole? We would probably all say that a donut has 1 hole, and some people might say that a straw has 2 holes, even though they're topologically equivalent. But what about a y-shaped tube? How holes does it have? It seems like the answer should be 3, but does anyone know for sure?

What about pores? There's a lot of them.

would any of them be holes? or openings?.. a donut hole goes right through.. if you are shot, and you have a hole , it goes right through you, but.. a body has no holes, unless you have your piercings maybe.. but, there are lots of openings

Originally posted by MIODude
would any of them be holes? or openings?.. a donut hole goes right through.. if you are shot, and you have a hole , it goes right through you, but.. a body has no holes, unless you have your piercings maybe.. but, there are lots of openings

I don't know about you, but baked beans and sausage go right through me.

Originally posted by AThousandYoung
What's a "hole"?

Think of an apple where n worms have entered the apple, chewed their way through and come out again, without crossing their own or each others' paths. Say that an solid object is a 'solid torus of genus n' or a 'solid n-holed torus' if (topologically speaking) it looks like what's left of the apple.

I don't know if there's a standard name for a Y-tube - it's homotopy equivalent to a figure-of-eight, if that's any help.

Originally posted by Acolyte
I don't know if there's a standard name for a Y-tube - it's homotopy equivalent to a figure-of-eight, if that's any help.

Wait a minute, is that true? A double-torus or figure-eight has 2 rings, each with one "in" and one "out". But a y-tube has 3 "holes", each with one "in" and two "outs". I don't think you can stretch a figure-eight into a y-tube without tearing the surface or eliminating some holes.