What specifically constitutes a hole is somewhat ambiguous, but if you pull on the thread a bit, you’ll probably agree that it’s a topological quality and that homotopy groups and homology are good candidates. The most grounded way to approach the topic is with simplicial homology.
5714@lemmy.dbzer0.com
on 09 Jun 04:17
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a sphere is a plane folded in on itself, and spheres have no (one-dimensional) holes. but spheres do have a two-dimensional hole, which is basically a way of saying they’re hollow.
a circle is a line folded in on itself, and circles have one (one-dimensional) hole.
edit: the claim that circles and straws are homotopic is basically a fancy way of saying: “if you place a straw upright on a table and flatten it by smashing your hand down on it, you will end up with a circle.”
Crankenstein@lemmy.world
on 09 Jun 05:06
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This is one of those “if you cut a hole in a net, it then has less holes than before” type arguments and I’m all here for it.
chiliedogg@lemmy.world
on 09 Jun 18:10
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I think it would still techically be more hole since a larger total area would be hole.
I would be fewer holes, though.
gravitas_deficiency@sh.itjust.works
on 10 Jun 03:06
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A lot of transportation has an equivalent amount of doors, and there a lot of house, apartment buildings, offices… You use a lot more doors every day than you do wheels.
Not even close; even an electric car has far more wheels than doors. Every rotating mechanism is made up of wheels, some geared others with groves for belts to run in.
Even just considering the ones that you see, there are tires and hubs which (for a car) means there are 8 wheels and only 4 or 5 doors. You could count the bonnet (hood) as a door and make it 6.
But there are hundreds of wheels, thousands in an ICE vehicle.
Depends on how broadly you define door. When you think about it, a transistor could be considered as a sort of door for electrons, for example, and there are 19 billion transistors in the processor of an iPhone
iAvicenna@lemmy.world
on 09 Jun 08:09
nextcollapse
a torus is not homotopic to a straw though unless you take the straw and glue it at its ends. a straw is homotopic to a circle, a torus is homotopic to product of two circles, Baldur’s gate is homotopic to a disk which is homotopic to a point unless we are talking about the game storage medium which used to be a CD which is also homotopic to a circle
What you said is stronger than being homotopic. homotopic is weaker, for instance a line is homotopic to a point, By taking the straw (even if it has thickness) and just shrinking it along its longer axis you eventually arrive at a circle. If it has thickness you will arrive at a band and then you can also retract radially to arrive at a circle.
Even if it has thickness still homotopic to a circle. For instance a band with thickness is homotopic to a circle, you can retract along the radius to arrive at a circle that is inside the band. Similarly a plane, or a slab with thickness are all homotopic to a point.
Note that all of these are proved by using collections of transformations from the space to itself (not necessarily from the space to all of itself though, if it maps the space to a subset of it that is fine). So if you want to say something like “but you can also shrink a circle to eventually reach a point but it is not homotopic to a point” that won’t work because you are imagining transformation that maps a circle not into itself but to a smaller one.
ps: the actual definition of homotopy equivalence between “objects” is slightly more involved but intuitively it boils down to this when you imagine one space as a subset of the other and try to see if they are homotopy equivalent.
There’s a math joke I remember hearing ~10 years ago, I can’t remember the whole thing, but it was something about a mathematician not being able to tell the difference between a coffee mug and a donut, they have the same number of holes so they’re the same shape.
The throughput and containment of the object is the criteria for classification here.
Can the object passing through the hole be contained by the medium of the object that is subject to the “hole” classification? If yes, then the object has two holes, one which the passing object passes through to enter the object, and one which is passed through to exit the object.
If the object passing through the object being classified cannot be contained entirely within the classification object medium, then the classification object has one hole.
This kind of classification relies upon the context of the item’s usage, and is in fact a “contextually dependent” classification!
Take the straw for example:
When a straw is being used for drinking bubble tea, the straw has two holes when a boba is passing through. The straw has two holes for each ice crystal or clump of crystals that passes through.
Does the straw have two holes for a liquid? Good question! This is also a contextually dependent classification criteria, though this time it is a matter of reference frame! Do you consider a liqiud to be a macro expression of the fluid dynamics of the molecules comprising the medium? Then it is a whole, though I would suggest that the “whole” of the liquid in the container from which it is being drawn to be one “whole” and the liquid which is drawn into the straw during the vacuum action (from the initiation of the “pull” through to its conclusion) to be a new and unique “part” separated from the source volume and comprises a new “whole”.
Ok, so NOW if the newly separated volume of liquid being drawn into the straw is less than the total volume of the straw, the straw has two holes (one hole being drawn upon, and one hole into which the newly created liquid volume is being drawn into.
Are you very thirsty? Have you drawn more liquid through the straw than the volume of the straw itself? You could then say the straw only had one hole for the duration of that pull!
On the other hand, if you are defining each molecule within the liquid medium to be its own object, then the straw always has two holes.
I don’t personally subscribe to the notion that a straw is a single hole, since, in the abstract, my gut reaction is to define a hole as an absence of something, rather than a property of something else. Tools used to make holes (a shovel, an auger, a 3 hole punch, a gravitational singularity, etc.) all remove a part of the initial object, rather than “adding an absence” (ground media, paper circles, or the physical constants of dimensional spacetime, respectively).
Now that I’m thinking about it though, a straw is constructed by extrusion. The straw media is forced through a mold which defines the initial hole (the initially extruded straw media, which, as side note, is almost certainly trimmed to be cleanly cut to present as clean and uniform tip) and then subsequently, each straw would be severed at standard intervals to make the straw object. While considering this, I feel like it provides even more support for the “two hole argument” as each end of each straw must be independently and intentionally “formed” during the process of manufacturing.
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I don’t understand why a circle has one/a hole though.I don’t even know what a hole is.Edit: Ok, circles might not have holes, they have interiors?
Make sure you’re distinguishing between a circle and a disc.
What specifically constitutes a hole is somewhat ambiguous, but if you pull on the thread a bit, you’ll probably agree that it’s a topological quality and that homotopy groups and homology are good candidates. The most grounded way to approach the topic is with simplicial homology.
🕳
www.dndbeyond.com/magic-items/4699-portable-hole
<img alt="" src="https://lemmy.zip/pictrs/image/b09b19fa-a674-4910-9a1f-e5192ed6d45a.webp">
A circle is a plane folded on itself so the answer is technically 0 holes. But first what is a hole?
A goal?
a sphere is a plane folded in on itself, and spheres have no (one-dimensional) holes. but spheres do have a two-dimensional hole, which is basically a way of saying they’re hollow.
a circle is a line folded in on itself, and circles have one (one-dimensional) hole.
edit: the claim that circles and straws are homotopic is basically a fancy way of saying: “if you place a straw upright on a table and flatten it by smashing your hand down on it, you will end up with a circle.”
This is one of those “if you cut a hole in a net, it then has less holes than before” type arguments and I’m all here for it.
I think it would still techically be more hole since a larger total area would be hole.
I would be fewer holes, though.
But there’s more hole per hole
What gets bigger, the more you take away from it?
My love for a blue Dwarf.
More cheese -> more holes
More holes -> less cheese
Therefore: More cheese -> less cheese
The average person is a straw.
Not really, they’re some sort of tube, but they don’t classify as straws
I’m a series of tubes!
You’re the Internet?
Yes! You can call me… The lawnmower man!
(I’m seriously dating myself with that reference)
I remember thinking this was top notch graphics in 1992.
<img alt="" src="https://thespool.net/wp-content/uploads/2019/09/cropped-lawnmower-man.jpeg">
It was uncanny and disturbing back then. It’s uncanny, disturbing, and hilarious now.
This is a strawman argument.
I love you for this!
What size does a hole need to be to be a hole
In theory, the smallest hole possible would be a ring of atoms combined into a molecule with an empty center
benzene got that nanopussy
That is one way of putting it, a bit crude though…
I imagine you with a monocle and a top hat
This is the kind of content I got to lemmy for.
Twice as big as half a hole, obviously.
How about a pair of jeans?
If anyone wants to see an entertaining mathematician talk about this exact topic for 30 minutes, here you go:
youtu.be/ymF1bp-qrjU
And here’s Michael from VSauce talking about the topic:
youtu.be/egEraZP9yXQ
I knew this was going to be Stand-up Maths before I clicked the linked.
Reminds me of the old “Are there more doors or wheels in the world?” question
The answer is “yes”.
Definitely wheels. All that machinery with wheels for the belts, all transportation, toys, … I can’t fathom there being as many doors.
Unless I’m wooshed :D
A lot of transportation has an equivalent amount of doors, and there a lot of house, apartment buildings, offices… You use a lot more doors every day than you do wheels.
Not even close; even an electric car has far more wheels than doors. Every rotating mechanism is made up of wheels, some geared others with groves for belts to run in.
Even just considering the ones that you see, there are tires and hubs which (for a car) means there are 8 wheels and only 4 or 5 doors. You could count the bonnet (hood) as a door and make it 6.
But there are hundreds of wheels, thousands in an ICE vehicle.
A gear is not a wheel. That’s why it’s called a “gear” and a “wheel”.
Depends on how broadly you define door. When you think about it, a transistor could be considered as a sort of door for electrons, for example, and there are 19 billion transistors in the processor of an iPhone
One of my friends is a Taurus as well. He’s a car.
How many holes does he have?
At least 5. I’m unwilling to do a more thorough count, tho.
<img alt="" src="https://i.imgur.com/drZZywm.gif">
what an interesting looking Tesla
a torus is not homotopic to a straw though unless you take the straw and glue it at its ends. a straw is homotopic to a circle, a torus is homotopic to product of two circles, Baldur’s gate is homotopic to a disk which is homotopic to a point unless we are talking about the game storage medium which used to be a CD which is also homotopic to a circle
Wouldn’t a straw be the product of a circle and a line?
What you said is stronger than being homotopic. homotopic is weaker, for instance a line is homotopic to a point, By taking the straw (even if it has thickness) and just shrinking it along its longer axis you eventually arrive at a circle. If it has thickness you will arrive at a band and then you can also retract radially to arrive at a circle.
You are talking about a straw of zero wall thickness right? A real straw should be homo-whatever to a torus
Homotopic: Having the same (homo-) topological properties (-topic)
Even if it has thickness still homotopic to a circle. For instance a band with thickness is homotopic to a circle, you can retract along the radius to arrive at a circle that is inside the band. Similarly a plane, or a slab with thickness are all homotopic to a point.
Note that all of these are proved by using collections of transformations from the space to itself (not necessarily from the space to all of itself though, if it maps the space to a subset of it that is fine). So if you want to say something like “but you can also shrink a circle to eventually reach a point but it is not homotopic to a point” that won’t work because you are imagining transformation that maps a circle not into itself but to a smaller one.
ps: the actual definition of homotopy equivalence between “objects” is slightly more involved but intuitively it boils down to this when you imagine one space as a subset of the other and try to see if they are homotopy equivalent.
A CD is clearly homotopic to a torus, though…
And the walls of a straw do have thickness…
A straw goes:
Gas - solid - gas - solid - gas
If solid torus yes, if just the regular torus (surface of the solid torus) no. CD is homotopic to a circle and so is a solid torus.
OK, that’s my ignorance. I didn’t realise toruses were usually hollow.
Thank you for letting me know, you’re right and I’ve learnt something.
Zero
Thinking about it, humans have one less hole than I would’ve guessed, since the tube from our mouth to our anus sort of makes us a complicated straw.
The human body is just a series of tubes.
The internet and I have that in common, I guess.
darfuck is homotopic?
It’s what I identify as on Grindr
I’d never heard of it either.
There’s a math joke I remember hearing ~10 years ago, I can’t remember the whole thing, but it was something about a mathematician not being able to tell the difference between a coffee mug and a donut, they have the same number of holes so they’re the same shape.
Edit: <img alt="" src="https://mander.xyz/pictrs/image/be7fc7d4-d8c2-44d1-8633-4a6a7053d89d.jpeg">
I also was also told once that since the nostrils and mouth are connected holes which lead to the asshole, humans are homotopic with fidget spinners.
topologically same
The throughput and containment of the object is the criteria for classification here.
Can the object passing through the hole be contained by the medium of the object that is subject to the “hole” classification? If yes, then the object has two holes, one which the passing object passes through to enter the object, and one which is passed through to exit the object.
If the object passing through the object being classified cannot be contained entirely within the classification object medium, then the classification object has one hole.
This kind of classification relies upon the context of the item’s usage, and is in fact a “contextually dependent” classification!
Take the straw for example:
When a straw is being used for drinking bubble tea, the straw has two holes when a boba is passing through. The straw has two holes for each ice crystal or clump of crystals that passes through.
Does the straw have two holes for a liquid? Good question! This is also a contextually dependent classification criteria, though this time it is a matter of reference frame! Do you consider a liqiud to be a macro expression of the fluid dynamics of the molecules comprising the medium? Then it is a whole, though I would suggest that the “whole” of the liquid in the container from which it is being drawn to be one “whole” and the liquid which is drawn into the straw during the vacuum action (from the initiation of the “pull” through to its conclusion) to be a new and unique “part” separated from the source volume and comprises a new “whole”.
Ok, so NOW if the newly separated volume of liquid being drawn into the straw is less than the total volume of the straw, the straw has two holes (one hole being drawn upon, and one hole into which the newly created liquid volume is being drawn into.
Are you very thirsty? Have you drawn more liquid through the straw than the volume of the straw itself? You could then say the straw only had one hole for the duration of that pull!
On the other hand, if you are defining each molecule within the liquid medium to be its own object, then the straw always has two holes.
I don’t personally subscribe to the notion that a straw is a single hole, since, in the abstract, my gut reaction is to define a hole as an absence of something, rather than a property of something else. Tools used to make holes (a shovel, an auger, a 3 hole punch, a gravitational singularity, etc.) all remove a part of the initial object, rather than “adding an absence” (ground media, paper circles, or the physical constants of dimensional spacetime, respectively).
Now that I’m thinking about it though, a straw is constructed by extrusion. The straw media is forced through a mold which defines the initial hole (the initially extruded straw media, which, as side note, is almost certainly trimmed to be cleanly cut to present as clean and uniform tip) and then subsequently, each straw would be severed at standard intervals to make the straw object. While considering this, I feel like it provides even more support for the “two hole argument” as each end of each straw must be independently and intentionally “formed” during the process of manufacturing.
Thoughts?
Tl;dr, I was just looking for memes
The true answer involves integrals imo (my calc is rusty so I’m not gonna bother trying lol)
Think of a box with a hole arrangement that allows us to look through it if we are correctly positioned.
Would anyone dare to say that such a thing is possible to achieve with only one holes? (I’m not allowing holes in corners and edges to make my point)
A straw has 2 holes.