Sphere in Cube: Can it be Defined?

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Discussion Overview

The discussion revolves around the concept of defining a "disfigured sphere" that can approximate a cube mathematically. Participants explore the geometric implications of rounding the corners of a cube and the mathematical frameworks that could support such transformations, including references to NURBS (Non-Uniform Rational B-Splines) and Euclidean geometry.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire about the definition and implications of a "disfigured sphere" in relation to a cube.
  • There are references to mathematical expressions, such as ##x^8+y^8=(1/8)##, as potential analogies for the discussion.
  • Participants discuss the possibility of rounding the corners of a cube and question whether this can be considered a form of a disfigured sphere.
  • One participant mentions that NURBS could allow for the distortion of a sphere, similar to how a circle can be represented exactly in NURBS spline.
  • There is a suggestion that Euclidean geometry could facilitate the rounding of corners, but the exact requirements and implications remain unclear.
  • A participant expresses a desire to learn more about Euclidean and non-Euclidean geometry to better understand the topic.
  • Another participant asserts that the question does not pertain to non-Euclidean geometry, indicating a divergence in understanding the geometric context.

Areas of Agreement / Disagreement

Participants express differing views on the clarity and relevance of the original question regarding the disfigured sphere and its relationship to geometry. Some find the question valid and interesting, while others consider it vague or misdirected. There is no consensus on the specific geometric frameworks applicable to the discussion.

Contextual Notes

Participants acknowledge that the question may have no practical applications, yet they consider it a valid inquiry. There are references to various mathematical concepts, but the discussion lacks resolution on the definitions and implications of the terms used.

Atlas3
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Can it be defined a disfigured sphere to approximate a cube mathematically? 8 corners equilateral to some extent. Not exact.
 
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Do you mean something analogous to say
##x^8+y^8=(1/8)## ?
https://www.desmos.com/calculator/k30qaemomp
k30qaemomp.png
 
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robphy said:
Do you mean something analogous to say
##x^8+y^8=(1/8)## ?
https://www.desmos.com/calculator/k30qaemomp
k30qaemomp.png
This is interesting. But fit the sphere in the cube in 3 dimensions. Might be a space with limits bounding a unit cube with a sphere in an equivalent space is what I'm trying to resolve possibly. Thanks this was news to me.
 
You are repeatedly asking questions that are simply too vague to be answered. What exactly do you mean by a disfigured sphere? Certainly, you can round the corners of a cube as close to the cube itself as you wish. Is that a "disfigured" sphere?
 
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HallsofIvy said:
You are repeatedly asking questions that are simply too vague to be answered. What exactly do you mean by a disfigured sphere? Certainly, you can round the corners of a cube as close to the cube itself as you wish. Is that a "disfigured" sphere?
Yes it is. The effort by Rohphy graphically showed that. What type of geometry would allow that rounding. What mathematics in the academic sense. The only thing I know of isn't solid. It's a nurbs.
 
Atlas3 said:
Yes it is. The effort by Rohphy graphically showed that. What type of geometry would allow that rounding. What mathematics in the academic sense. The only thing I know of isn't solid. It's a nurbs.
I was asking about a disfigured sphere because a circle can be exact in nurbs spline. I thought possibly so could a sphere but control points allow a distortion of the figure.
 
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Atlas3 said:
Yes it is. The effort by Rohphy graphically showed that.

What Rohphy showed is not the rounding of the corners of a square. Although rounding of the corners of a square is certainly possible.

What type of geometry would allow that rounding..

You can do it in Euclidean geometry. I have no idea what you want more.
 
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micromass said:
What Rohphy showed is not the rounding of the corners of a square. Although rounding of the corners of a square is certainly possible.
You can do it in Euclidean geometry. I have no idea what you want more.
I feel that is sufficient for me. More than I can do however. It wasn't vague just simple yet very complicated in practice. I feel good about asking such a question in this forum. There is great knowledge here. It may be vague to some but not to others. I realize such a question may have no practical purposes. But it's a valid question if there is an answer. I cannot expect everyone to take time to reply.
 
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Atlas3 said:
Yes it is. The effort by Rohphy graphically showed that. What type of geometry would allow that rounding. What mathematics in the academic sense. The only thing I know of isn't solid. It's a nurbs.
Choose a radius, "r" (the smaller r is, the closer the "rounded cube" is to the actual cube). From any corner of the cube, measure along one edge a distance r. From that point measure along either of the two faces that meet in that edge, perpendicular to the edge, a distance r. From that point, measure along a line perpendicular to the face, into the cube, a distance r. Using that point as center, construct a sphere with radius r. Those 8 spheres will "round" the 8 corners of the sphere.
 
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  • #10
For future study, I am going to gain understanding of Euclidean Geometry. It seems quite a necessary next step. It wasn't a part of my undergraduate studies. Thank you all for your replies. I like these different ideas. It seems as though the Euclidean Geometry is the technique I need to grasp.
 
  • #11
"Euclidean Geometry" is usually taught in secondary school, not college!
 
  • #12
I had Geometry in High School. But The mapping of one space to another was taught in Linear Algebra in college. I think what I need is an extension of that Mathematics of Spaces. I could be wrong.
 
  • #13
I made a mistake above I think. It is non-Euclidean geometry I desire to know more about. Any thoughts?
 
  • #14
Your question has nothing to do with non-Euclidean geometry.
 

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