Talk:2625: Field Topology

Explain xkcd: It's 'cause you're dumb.
Revision as of 18:51, 27 May 2022 by 172.70.85.177 (talk)
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First 172.70.86.64 12:50, 27 May 2022 (UTC)

Why is football on the two-hole field? Where are the holes? I don't think the goal posts in American football introduce any since they're not closed. Maybe it's soccer? 172.69.68.88 12:58, 27 May 2022 (UTC)

Well, you might still be able to call them holes. They would be if they were fully rectangles. --BlackBeret (talk) 12:59, 27 May 2022 (UTC)
Gridiron football's field contains two areas (the endzones) that can be thought of as not being part of the "normal" field of play, for lack of a better way of saying that pre-coffee. Association football likewise has the areas within the nets. Noëlle (talk) 13:05, 27 May 2022 (UTC)
My immediate thoughts were also that football (soccer) and football (gridiron) are the same, or indeed the other way round. In both cases the closed hole (assuming not a Y-like vertical holder, but H-like as per rugby football) plays no more or less topological part. Threading through the hole from behind has no relevence in either, and in fact defining it as a region that is 'a special enclosed gap with meaning' (which doesn't really matter in the topology sense, just like golf would be a topologically hole-less surface and as a coffee-cup's inside 'dimple' doesn't count, just its handle-hole that makes it equivalent to a doughnut) actually counts for something in association football. 172.70.162.155 13:32, 27 May 2022 (UTC)
It's not the space bounded by the goal that is the 'hole' - it's the goal post itself (or in the case of the high jump, it's the bar, not the space under it). The reason soccer doesn't have 'holes' where the goals are is that they're positioned on the edge of the playable area - you can't play around the bars, because as soon as you cross the goal line you're out of play. And it doesn't matter whether it's a Y-shaped or H-shaped goal - topologically, they both form one continuous 'hole'. 172.70.91.80 13:37, 27 May 2022 (UTC)
I don't think that's the reason why soccer doesn't have holes. The goalposts in football are also outside the playable area, and so are the poles in volleyball. I think soccer is listed as zero-holes because soccer goals are typically not fixed to the field, and are instead separate objects that can be dragged around and removed from the field. On the other hand, the same is true of volleyball and badminton nets (and those nets contain many holes!) so the comic seems a bit inconsistent.172.70.175.146 14:05, 27 May 2022 (UTC)
Speaking from a "football is soccer" nation (well, mostly, the exceptional subregions would argue that it's rugby) a soccer goal is typically not draggable around the field, but permanent (or a unit frame that has to be painstakingly hoisted out of the ground if you don't want them in your football stadium, when you repurpose it for other purposes) and it's only the optional net that gets added to the park's permanent goalposts for the official five-aside competition evening or day of the weekend. Draggable goalposts need a further level of intermediate organisation that goes beyond the typical "shipping container with windows cut in it (with shutters bolted over them) as a cheap changing room/officials' cabin" that might be found near the edge of the field but rarely even has as much as a corner flag left in them, between games".
I presume that US 'football' posts are considered holes because they are an infinitely-tall window (even though the delineating poles only reach so high) that is a meaningful slice (where the goal is, you have to loop around it in mutually different unsimplifiable paths to reach the other side), but then that should make for two holes per end, if you count getting a field-goal and then returning round the sides (or vice-versa) as another valid surface-path.
...but, yeah, I can imagine the problem of definition (and cultural famiarity) here is going to produce more problems even than the understanding of topology. One of the less internationally-accepted comics, this. 172.70.85.177 18:51, 27 May 2022 (UTC)

Tetherball, in many variants, does contain an obstruction -- the pole, which you're not allowed to touch. The Topology Department is getting tired of having to switch out the fields. Noëlle (talk) 13:05, 27 May 2022 (UTC)

But you can surely jump over it, so it's topologically the same as a zero-height pole... 172.70.162.155 13:32, 27 May 2022 (UTC)

Croquet has six hoops and a peg. How does that make for nine holes? Is it including the opponents' two balls as holes? And if so, why aren't opposing players counted as holes in the other sports? 172.70.91.80 13:26, 27 May 2022 (UTC)

American football goals are Y-shaped. Rugby goals are H-shaped. Did... did Randall get those confused? Also, I fail to see how basketball and American football get two, croquet gets a bunch, but soccer gets zero. Aren't soccer goals (in-game at least) basically the same shape as croquet wickets, just waaaay bigger? Granted, I don't know anything about topology and I came to this wiki specifically cuz I'm dumb, so I'd love if someone could splain this all for me ;) --mezimm 172.69.69.170 13:37, 27 May 2022 (UTC)

The soccer goal has a net, so the ball can't go through it. Topologically it's just a wall (Randall seems to be ignoring all the tiny holes in netting, presumaby because they're smaller than the balls so they're insignificant to the sports). Barmar (talk) 14:10, 27 May 2022 (UTC)
I agree with that explanation - the net is the only thing that makes the soccer field not to have holes. It should be included in the comic explanation.
The hole for the volleyball only makes sense taking in account that the bottom of the net doesn't reach the floor, although this space is not used in the game.--Pere prlpz (talk) 14:18, 27 May 2022 (UTC)
I agree about soccer; the explanation should be that soccer goals (with net) are topologically part of the plane. The same is true of ice hockey, even though you can travel "around" the net, it is topologically part of the field with no holes. As for (American) football, the topology only makes sense for H-shaped goals, which are more often seen on primary/secondary play fields than in higher level play. Aramisuvla (talk) 16:03, 27 May 2022 (UTC)

The group link pointing to group (mathematics) doesn't bear any relation with the sentence or the comic. I would remove the link.--Pere prlpz (talk) 14:18, 27 May 2022 (UTC)