How does the parity of a dimension affect its properties?

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Does the parity of the dimension of $mathbbR^n$ affect its structure/properties? As in, does it make a difference if $n$ is even or odd?










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  • What kinds of properties specifically are you interested in?
    – j.c.
    2 hours ago






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    There are many differences between even and odd dimensions, but without more details it is not clear what direction you want answers. Examples: Complex/symplectic structures do not exist on odd dimensional spaces. Contact structures do not exist on even dimensional spaces.
    – Thomas Rot
    2 hours ago














up vote
1
down vote

favorite












Does the parity of the dimension of $mathbbR^n$ affect its structure/properties? As in, does it make a difference if $n$ is even or odd?










share|cite|improve this question









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user2192320 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.



















  • What kinds of properties specifically are you interested in?
    – j.c.
    2 hours ago






  • 3




    There are many differences between even and odd dimensions, but without more details it is not clear what direction you want answers. Examples: Complex/symplectic structures do not exist on odd dimensional spaces. Contact structures do not exist on even dimensional spaces.
    – Thomas Rot
    2 hours ago












up vote
1
down vote

favorite









up vote
1
down vote

favorite











Does the parity of the dimension of $mathbbR^n$ affect its structure/properties? As in, does it make a difference if $n$ is even or odd?










share|cite|improve this question









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Does the parity of the dimension of $mathbbR^n$ affect its structure/properties? As in, does it make a difference if $n$ is even or odd?







nt.number-theory linear-algebra gn.general-topology real-analysis






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edited 2 hours ago









Thomas Rot

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  • What kinds of properties specifically are you interested in?
    – j.c.
    2 hours ago






  • 3




    There are many differences between even and odd dimensions, but without more details it is not clear what direction you want answers. Examples: Complex/symplectic structures do not exist on odd dimensional spaces. Contact structures do not exist on even dimensional spaces.
    – Thomas Rot
    2 hours ago
















  • What kinds of properties specifically are you interested in?
    – j.c.
    2 hours ago






  • 3




    There are many differences between even and odd dimensions, but without more details it is not clear what direction you want answers. Examples: Complex/symplectic structures do not exist on odd dimensional spaces. Contact structures do not exist on even dimensional spaces.
    – Thomas Rot
    2 hours ago















What kinds of properties specifically are you interested in?
– j.c.
2 hours ago




What kinds of properties specifically are you interested in?
– j.c.
2 hours ago




3




3




There are many differences between even and odd dimensions, but without more details it is not clear what direction you want answers. Examples: Complex/symplectic structures do not exist on odd dimensional spaces. Contact structures do not exist on even dimensional spaces.
– Thomas Rot
2 hours ago




There are many differences between even and odd dimensions, but without more details it is not clear what direction you want answers. Examples: Complex/symplectic structures do not exist on odd dimensional spaces. Contact structures do not exist on even dimensional spaces.
– Thomas Rot
2 hours ago










1 Answer
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Let me try to focus the question as follows: Suppose you wake up in a dark and empty space. Which properties can help you decide whether the space is even or odd-dimensional?



In the context of wave propagation, there is the fundamental difference that Huygens principle is only valid in odd-dimensional space, see Wave Propagation in Even and Odd Dimensional Spaces. Sharly defined wavefronts (think of ripples in a pond when you throw a stone in) need an odd number of spatial dimensions, in even-dimensional space the wavefront decays with a long tail. (The study of this difference goes back to Volterra and Hadamard.)



So to test for even/odd dimensionality you only need to shout in empty space. If you hear an echo you live in an even number of spatial dimensions.






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  • In odd dimensions $-1$ is orientation reversing.
    – Liviu Nicolaescu
    8 mins ago










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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
6
down vote













Let me try to focus the question as follows: Suppose you wake up in a dark and empty space. Which properties can help you decide whether the space is even or odd-dimensional?



In the context of wave propagation, there is the fundamental difference that Huygens principle is only valid in odd-dimensional space, see Wave Propagation in Even and Odd Dimensional Spaces. Sharly defined wavefronts (think of ripples in a pond when you throw a stone in) need an odd number of spatial dimensions, in even-dimensional space the wavefront decays with a long tail. (The study of this difference goes back to Volterra and Hadamard.)



So to test for even/odd dimensionality you only need to shout in empty space. If you hear an echo you live in an even number of spatial dimensions.






share|cite|improve this answer






















  • In odd dimensions $-1$ is orientation reversing.
    – Liviu Nicolaescu
    8 mins ago














up vote
6
down vote













Let me try to focus the question as follows: Suppose you wake up in a dark and empty space. Which properties can help you decide whether the space is even or odd-dimensional?



In the context of wave propagation, there is the fundamental difference that Huygens principle is only valid in odd-dimensional space, see Wave Propagation in Even and Odd Dimensional Spaces. Sharly defined wavefronts (think of ripples in a pond when you throw a stone in) need an odd number of spatial dimensions, in even-dimensional space the wavefront decays with a long tail. (The study of this difference goes back to Volterra and Hadamard.)



So to test for even/odd dimensionality you only need to shout in empty space. If you hear an echo you live in an even number of spatial dimensions.






share|cite|improve this answer






















  • In odd dimensions $-1$ is orientation reversing.
    – Liviu Nicolaescu
    8 mins ago












up vote
6
down vote










up vote
6
down vote









Let me try to focus the question as follows: Suppose you wake up in a dark and empty space. Which properties can help you decide whether the space is even or odd-dimensional?



In the context of wave propagation, there is the fundamental difference that Huygens principle is only valid in odd-dimensional space, see Wave Propagation in Even and Odd Dimensional Spaces. Sharly defined wavefronts (think of ripples in a pond when you throw a stone in) need an odd number of spatial dimensions, in even-dimensional space the wavefront decays with a long tail. (The study of this difference goes back to Volterra and Hadamard.)



So to test for even/odd dimensionality you only need to shout in empty space. If you hear an echo you live in an even number of spatial dimensions.






share|cite|improve this answer














Let me try to focus the question as follows: Suppose you wake up in a dark and empty space. Which properties can help you decide whether the space is even or odd-dimensional?



In the context of wave propagation, there is the fundamental difference that Huygens principle is only valid in odd-dimensional space, see Wave Propagation in Even and Odd Dimensional Spaces. Sharly defined wavefronts (think of ripples in a pond when you throw a stone in) need an odd number of spatial dimensions, in even-dimensional space the wavefront decays with a long tail. (The study of this difference goes back to Volterra and Hadamard.)



So to test for even/odd dimensionality you only need to shout in empty space. If you hear an echo you live in an even number of spatial dimensions.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited 46 mins ago

























answered 2 hours ago









Carlo Beenakker

69.2k8155260




69.2k8155260











  • In odd dimensions $-1$ is orientation reversing.
    – Liviu Nicolaescu
    8 mins ago
















  • In odd dimensions $-1$ is orientation reversing.
    – Liviu Nicolaescu
    8 mins ago















In odd dimensions $-1$ is orientation reversing.
– Liviu Nicolaescu
8 mins ago




In odd dimensions $-1$ is orientation reversing.
– Liviu Nicolaescu
8 mins ago










user2192320 is a new contributor. Be nice, and check out our Code of Conduct.









 

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