Editing 2529: Unsolved Math Problems

Jump to: navigation, search

Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.

The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision Your text
Line 8: Line 8:
  
 
==Explanation==
 
==Explanation==
Math has many problems that remain "unsolved." This is not simply a matter of finding the correct numbers on both sides of an equal sign, but usually require proving or finding a counterexample to some conjecture, or explaining some property of some mathematical object. Sometimes this might involve extending an existing proof to a wider range of numbers like reals, complex numbers, or matrices.
+
{{incomplete|Created by a EULER FIELD GÖDEL-ESCHER-KURT-HALSEY STRANGE "CURVE" WALKING RANDOMLY ON A HYPERDIMENSIONAL FOUR-SIDED QUANTUM KLEIN MANIFOLD. Do NOT delete this tag too soon.}}
  
A concrete problem is one that is very obviously connected to a real world process, while an abstract problem is one which seems unconnected to actual problems. In modern math, many problems tend to be very abstract, requiring complicated notation to adequately state the problem in the first place, like many of the {{w|millennium problems}}. On the other hand, many unsolved problems are very concrete, such as the {{w|Collatz conjecture}}. Additionally, there are the many problems related to {{w|Packing problem|packing objects into spaces}} which are often very difficult to solve though quite easy to state. Finally, Randall describes a third category of "cursed problems," that have strange, seemingly random behavior, such as the behavior of turbulence or the distribution of prime numbers.
+
Math has many problems that remain unsolved. Some problems are easy to understand, but difficult to form a proof for, such as the {{w|Collatz conjecture}}. Others are unsolved because they require an extremely high level of knowledge just to recognize the parts, so there are few people who can work on them and even they have trouble.
  
In the first panel, Ponytail describes a weird abstract problem. Her description seems to be a meaningless jumble of terms that are either mathematical or just ''sound'' mathematical. And the mathematical terms are from disparate branches of mathematics: group theory, topology, and calculus.  
+
In mathematics, a concrete problem is one that is very obviously connected to a real world process while an abstract problem is one which seems unconnected to actual problems. In modern math many problems tend to be very abstract requiring complicated notation to adequately state the problem in the first place like many of the {{w|millennium problems}}. On the other hand many unsolved problems are very concrete, for example there are very many problems related to packing objects into spaces which are very difficult to solve, although quite easy to state. Finally cursed problems are problems that have strange, seemingly random behavior such as, for example the collatz conjecture or the distribution of primes.
  
*'''Euler field:''' An Euler vector field represents a space where every point is rotating with its own speed and direction. The name "Euler field", however, is something like "John Smith" - fields are very common algebraic structures, and {{w|Leonard Euler}} was a prolific Swiss mathematician who influenced {{w|List_of_things_named_after_Leonhard_Euler|so many areas of study}} that some of his discoveries are named after whoever wrote about them next, just to avoid naming everything after him.
+
In the first panel, Ponytail describes a weird abstract problem. Her description seems to be a meaningless jumble of terms that are either mathematical or just ''sound'' mathematical. And the mathematical terms are from disparate branches of mathematics: group theory, topology, calculus. It's full of what seem to be [[Malamanteau|malamanteaus]]: "quasimonoid" combines the prefix "quasi" (meaning "partially" or "seemingly") and "monoid" (an object from group theory) and is probably meant to evoke the character {{w|Quasimodo}} from ''The Hunchback of Notre-Dame'' (although quasimonoids are a type of algebraic object, namely a non-associative {{w|monoid}}); "Gödel-Klein" combines {{w|Kurt Gödel}}, a 20th-century mathematician who studied logic and philosophy (he's most well known for {{w|Gödel's incompleteness theorems}}) and {{w|Felix Klein}}, a 19th century mathematician who studied group theory and geometry, who probably never collaborated; "sondheim calculus" refers to {{w|Stephen Sondheim}}, one of the most successful composers and lyricists of American musical theatre -- the producer of his musical "Into the Woods" once [[https://www.indiewire.com/2015/01/watch-singing-sondheim-is-like-calculus-in-into-the-woods-behind-the-scenes-video-exclusive-189507/ remarked]] that “Singing Stephen Sondheim is like calculus for singers and actors.”; and "conjection" may combine conjecture and conjunction, or be a joke on pros and cons plus projection. Finally she asks whether the problem statement is ill-formed; considering that it's mostly gibberish, this may be true.
*'''{{w|Manifold}}:''' A manifold is a topological space which is locally Euclidean - the shortest distance between two points is a straight line, the ratio between a circle's circumference and diameter is always pi, parallel lines are always the same distance apart, everything generally behaves the way you'd expect. A globe is a two-dimensional manifold, because a small-enough area is indistinguishable from a flat map. Using manifolds as an example of impenetrably occult maths may be a nod to the Tom Lehrer song "Lobachevsky", which makes a similar joke about "the analytical algebraic topology of locally Euclidean metrizations of infinitely differentiable Riemannian manifolds (Bozhe moi!)".
 
*'''{{w|Hypergroup}}:''' An ''algebraic structure'', like arithmetic, is a set of well-defined operations (addition, subtraction, multiplication, division) mapping inputs to outputs over a domain of elements (the real numbers). A ''hyperstructure'' is an algebraic structure including an operation that maps a single input to multiple outputs - the simplest example is the square root, which maps a positive number like 4 to both positive and negative 2. A ''hypergroup'' is a hyperstructure with an operation that takes a pair of input elements, and, depending on which pair, can output every element or combination of elements in its domain... but also preserves association (1 + 2 + 3 = 6 whether you start by adding 1 + 2 or 2 + 3) and reproduction (if either input is "the entire domain", then the output will still be the entire domain). It's a decent indication of how abstract a hypergroup is that it takes at least three to five sub-definitions to make it remotely understandable.
 
*'''Isomorphic:''' {{w|Isomorphism}} describes whether all the attributes of one structure can be mapped to properties of another structure. The structures usually have to be of the same type; it is unclear how a hypergroup would map to a "conjection".
 
*'''Gödel-Klein:''' {{w|Kurt Gödel}} was a 20th-century mathematician who studied logic and philosophy (he's most well known for {{w|Gödel's incompleteness theorems}}) and {{w|Felix Klein}} was a 19th century mathematician who studied group theory and geometry; the two probably never collaborated.
 
*'''Meta-algebra:''' Not a real term, though derived from the real term {{w|Metamathematics}}.
 
*'''ϵ<0:''' Another joke term. In analysis, {{w|ϵ}} is usually defined to be an arbitrarily small ''positive'' number.
 
*'''quasimonoid:''' A [[Malamanteau|malamanteau]], combining the prefix "quasi" (meaning "partially" or "seemingly") and "monoid" (an object from group theory) and is probably meant to evoke the character {{w|Quasimodo}} from ''The Hunchback of Notre-Dame'' (although quasimonoids are a type of algebraic object, namely a non-associative {{w|monoid}})
 
*'''Sondheim Calculus:''' This refers to {{w|Stephen Sondheim}}, one of the most successful composers and lyricists of American musical theatre -- the producer of his musical "Into the Woods" once [https://www.indiewire.com/2015/01/watch-singing-sondheim-is-like-calculus-in-into-the-woods-behind-the-scenes-video-exclusive-189507/ remarked] that "Singing Stephen Sondheim is like calculus for singers and actors."
 
*'''conjection:''' This may combine conjecture and conjunction, or be a joke on pros and cons plus projection.  
 
  
Finally she asks whether the problem statement is ill-formed; considering that it's mostly gibberish, this may be true.
+
Many real unsolved math problems appear similarly abstract. One example is the {{w|Hodge Conjecture}}, a {{w|Millennium Prize Problems|Millenium Prize}} problem. It states "Let X be a non-singular complex projective manifold. Then every Hodge class on X is a linear combination with rational coefficients of the cohomology classes of complex subvarieties of X." These words may appear nonsensical to a layman.
  
Many real unsolved math problems appear similarly abstract. One example is the {{w|Hodge conjecture}}, a {{w|Millennium Prize Problems|Millennium Prize}} problem. It states "Let X be a non-singular complex projective manifold. Then every Hodge class on X is a linear combination with rational coefficients of the cohomology classes of complex subvarieties of X." These words may appear nonsensical to a layperson. And even to an expert, the question is `abstract'. (Given a specific manifold, even an abelian fourfold, how on earth do you determine if a given 2,2 class is a cycle?)
+
In the second panel, Cueball describes a concrete {{w|random walk}} problem, and then mentions that this somehow has applications in three unrelated fields. This is actually not uncommon. The Wikipedia article says "random walks have applications to engineering and many scientific fields including ecology, psychology, computer science, physics, chemistry, biology, economics, and sociology. Walking randomly on a grid never visiting any square twice is known as a {{w|self-avoiding walk}}. This panel may have been inspired by some of the tricky unsolved problems about self-avoiding walks. Many of these problems have to do with proving rigorously properties of random walks that have been guessed by physics intuition, so these problems are connected to physics. The part about the maximum number of points in a line is reminiscent of problems in combinatorial geometry, which often involve counting points lying on different lines.  "
  
In the second panel, Cueball describes a concrete {{w|random walk}} problem, and then mentions that this somehow has applications in three unrelated fields. This is actually not uncommon. The Wikipedia article says that "random walks have applications to engineering and many scientific fields including ecology, psychology, computer science, physics, chemistry, biology, economics, and sociology. Walking randomly on a grid never visiting any square twice is known as a {{w|self-avoiding walk}}." This panel may have been inspired by some of the tricky unsolved problems about self-avoiding walks. Many of these problems have to do with rigorously proving properties of random walks that have been guessed by physics intuition, so these problems are connected to physics. The part about the maximum number of points in a line is reminiscent of problems in combinatorial geometry, which often involve counting points lying on different lines. Python code simulating this situation can be found [http://colab.research.google.com/drive/1nWrByCGBckwVdbAwow7tCYTOvqObYXyR?usp=sharing here]. C++ code simulating this situation can be found [http://github.com/AMindToThink/WeirdlyConcreteXKCD here].
+
In the final panel, Megan is looking at a strange curve that seems to have no consistent pattern. At the bottom it's mostly straight, with a few little wobbles. In the middle it looks like a wild, high-frequency wave that suddenly bursts and then dies down. And the top is a spiral that looks like a question mark or a Western-style {{w|Crosier}}. She wonders if this could even be mathematical. Considering the weird shapes that come from plotting some mathematical processes (e.g. the {{w|Mandelbrot set}}), it could well be.
  
In the final panel, Megan is looking at a strange curve that seems to have no consistent pattern. At the bottom it's mostly straight, with a few little wobbles. In the middle it looks like a wild, high-frequency wave that suddenly bursts and then dies down. And the top is a spiral that looks like a question mark or a Western-style {{w|Crosier}}. She wonders if this could even be mathematical.
+
==Transcript==
On one hand, considering the weird shapes that come from plotting some mathematical processes (e.g. the {{w|Mandelbrot set}}), it could well be. For example the unsolved {{w|Riemann hypothesis}}, another Millennium Prize problem, concerns the properties of {{w|File:RiemannCriticalLine.svg|a weird and at-first-glance random curve}}.  In number theory, the term "cursed curve" [https://www.quantamagazine.org/mathematicians-crack-the-cursed-curve-20171207/ has been used] to describe the [https://annals.math.princeton.edu/wp-content/uploads/annals-v173-n1-p13-s.pdf "split Cartan" modular curve] of level 13, which resisted attempts for many years to compute its [https://www.jstor.org/stable/10.4007/annals.2019.189.3.6 set of rational points].
+
{{incomplete transcript|Do NOT delete this tag too soon.}}
On the other hand, the question if could even be mathematical suggests that this may indeed not be a mathematical symbol. The curve looks like the unalome symbol, which is a Buddhist symbol which represents the path taken in life, or the journey to enlightenment. It could be argued that this indeed represents an unsolved problem, although not a mathematical one - which might then be part of the humoristic meaning.
 
  
The title text states that, despite decades of intensive study on the properties of the cursed curve, the best anyone's been able to come up with to explain its strangeness is "it's just like that." This lack of a satisfying explanation is commonplace with advanced math topics. As one famous example, the {{w|monster group}} ([https://youtu.be/mH0oCDa74tE explanation video]) is known to be the largest of a category of objects called {{w|sporadic groups}}. Similarly to the cursed curve in the comic, the monster group has a bizarre and complex structure which has, so far, managed to elude any logical explanation aside from "it's just like that."
 
 
==Transcript==
 
 
The Three Types Of Unsolved Math Problem
 
The Three Types Of Unsolved Math Problem
  
:[First box:] Weirdly Abstract
+
:First: Weirdly Abstract
:[Ponytail stands in front of an equation.]
+
:[Ponytail stands in front of an equation]
 
:Is the Euler Field Manifold Hypergroup Isomorphic to a Gödel-Klein Meta-Algebreic ε<0 Quasimonoid Conjection under Sondheim Calculus?
 
:Is the Euler Field Manifold Hypergroup Isomorphic to a Gödel-Klein Meta-Algebreic ε<0 Quasimonoid Conjection under Sondheim Calculus?
 
:Or is the question ill-formed?
 
:Or is the question ill-formed?
:⬙ℝ̇ℤ/Eℵ₅ [The Z is raised and underneath it is a double-ended arrow bent at a right angle. One points toward the R the other toward the Z. The ₅ is double-struck (𝟝) like the R and Z.]
+
:⬙ℝंℤ/Eℵ₅ The Z is raised and underneath it is a double-ended arrow bent at a right angle. One points toward the R the other toward the Z. The ₅ is double-struck like the and
  
 
:Second: Weirdly Concrete
 
:Second: Weirdly Concrete
Line 54: Line 41:
 
:Third: Cursed
 
:Third: Cursed
 
:[A Megan with unkempt hair stands next to a curve]
 
:[A Megan with unkempt hair stands next to a curve]
:What in God's name is going on with this curve?
+
:What in god's name is going on with this curve?
 
:Is it even math?
 
:Is it even math?
 
:[The curve starts at the bottom of the screen, rises straight upward, begins to wobble left and right a little. It lists to the left and the left-right motion increases, then decreases. It begins a large counter-clockwise arc, spiraling inwards twice, then ends]
 
:[The curve starts at the bottom of the screen, rises straight upward, begins to wobble left and right a little. It lists to the left and the left-right motion increases, then decreases. It begins a large counter-clockwise arc, spiraling inwards twice, then ends]
Line 63: Line 50:
 
[[Category: Comics featuring Ponytail]]
 
[[Category: Comics featuring Ponytail]]
 
[[Category: Math]]
 
[[Category: Math]]
[[Category:Comics with cursed items]] <!-- Some presumedly mathematical curve -->
 

Please note that all contributions to explain xkcd may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see explain xkcd:Copyrights for details). Do not submit copyrighted work without permission!

To protect the wiki against automated edit spam, we kindly ask you to solve the following CAPTCHA:

Cancel | Editing help (opens in new window)