It’s a hollow cylinder with a hole at each end.
It’s an extremely thick or concave disc with a hole through the center.
Neither answer is wrong.
Do not try to bend the hole—that’s impossible. Instead, only try to realize the truth: there is no hole.
A straw is simply a complete fistula with two openings but no holes.
So, how are things in Flavortown, anyway?
Funny, but not really. The two faces of a washer are separate things from each other, but there is one hole.
The human digestive system is a single hole that penetrates the body from one opening (lips) to another opening (anus)
This is what I was going to post.
I am young enough to remember paper straws, which were made by spiral-wrapping a 2" ribbon of wax-coated paper around a mandrel, heat-sealed at the seam and cut into appropriate length segments. Not very analogous to drilling.
I also am old enough, and I did think about paper straws, but as I was responding to a post talking about nearly all straws not being drilled.
Aren’t there two holes, in the sense a disc with two smaller discs stamped out of it has two holes, or a solid ball drilled from the surface only down to the center and not all the way through has no holes?
Topologically, a straw is equivalent to a donut. A donut has one hole. QED
An opening is not a hole. In this case, you have 3 openings, 1 hole. In the straw question, 2 openings, 1 hole. Same for a donut.
Topologically, if two spaces can be continuously deformed one into another, they may not be the “same”- take a Möbius strip and a regular strip- but they have the same number of holes if you consider a coffee cup and a doughnut to have the same number of holes.
Isn’t that 2 holes? I could be wrong, but then you should show me how to deform it into a doughnut (rather than a 2-holed doughnut).
Neither. It is a solid torus. Even mathematical experts can be found describing a torus as a ring with one hole, but that is incorrect. The torus is solid, it just happens to describe and inner area which is not fully encased.
If there are holes in your straw, it won’t work unless they are below the surface of the liquid.
Not necessarily. A hole means that the surface is not simply-connected. On a surface that is simply-connected, there is no place where you could draw a closed curve that cannot be shrunk to a point by traversing the surface. I bought a cup of coffee at a machine in the store the other day. The cup that it delivered to was a paper cylinder with no handle, which qualifies, by purposed use, as a coffee cup. There was no part of that surface that could not be described as simply-connected. It had no hole.
I was referring to Mangetout’s “drill 3 times into a solid object, meeting at the center” concept. The meeting at the center would not create another hole, nor opening. Topologically, there would be only one interior passage (hole), but 3 ways to enter it from the outside (openings).
That’s the one I meant, and I think it is homotopically equivalent to a figure-eight. Admittedly, I pictured this in my head and haven’t tried to write down a mathematical proof or anything like that.
ETA these solids don’t have an “inside”, just a connected complement (“outside”)
Speaking ex cathedra, the first homology group is Z. Therefore one hole. Although it is true that a solid donut has one hole, a torus, the surface of the donut, has two and the homology group is Z^2.
A properly made donut has thousands of holes.
Do I get to vote “no holes”? Its a flat object curved. Like a toilet paper roll, which is a flat piece of cardboard with opposite edges joined. No holes.