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Post Made Community Wiki by Ivan Gundyrev
add example for locally compact case
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Ivan Gundyrev
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Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.(Consider the induced path metric space on the following subset of the Euclidean plane: $(0,1]\times \{0\} \cup (0,1] \times \{1\} \cup \bigcup_{n=1}^{\infty} \{1/n\} \times [0,1]$$(0,1] \times \{ 0 \}\cup (0,1]\times \{1\}\cup \bigcup_{n=1}^{\infty}\{1/n\}\times [0,1] $.)

  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.

  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.

  4. if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space. (consider the graph of $sin(1/x)$$\sin(1/x)$ in the plane for positive $x$. )

I am interested in this problem in general, especially for the spaces with intrinsic metric.

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.(Consider the induced path metric space on the following subset of the Euclidean plane: $(0,1]\times \{0\} \cup (0,1] \times \{1\} \cup \bigcup_{n=1}^{\infty} \{1/n\} \times [0,1]$.)

  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.

  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.

  4. if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space. (consider the graph of $sin(1/x)$ in the plane for positive $x$. )

I am interested in this problem in general, especially for the spaces with intrinsic metric.

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.(Consider the induced path metric space on the following subset of the Euclidean plane: $(0,1] \times \{ 0 \}\cup (0,1]\times \{1\}\cup \bigcup_{n=1}^{\infty}\{1/n\}\times [0,1] $.)

  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.

  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.

  4. if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space. (consider the graph of $\sin(1/x)$ in the plane for positive $x$. )

I am interested in this problem in general, especially for the spaces with intrinsic metric.

add example for locally compact case
Source Link
Ivan Gundyrev
  • 141
  • 1
  • 1
  • 7

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.

    if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.(Consider the induced path metric space on the following subset of the Euclidean plane: $(0,1]\times \{0\} \cup (0,1] \times \{1\} \cup \bigcup_{n=1}^{\infty} \{1/n\} \times [0,1]$.)

  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.

    if $(X,d)$ is separable space then $\bar{X}$ is separable space.

  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.

    if $(X,d)$ is connected space then $\bar{X}$ is connected space.

  4. if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space.

    if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space. (consider the graph of $sin(1/x)$ in the plane for positive $x$. )

I am interested in this problem in general, especially for the spaces with intrinsic metric.

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.
  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.
  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.
  4. if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space.

I am interested in this problem in general, especially for the spaces with intrinsic metric.

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.(Consider the induced path metric space on the following subset of the Euclidean plane: $(0,1]\times \{0\} \cup (0,1] \times \{1\} \cup \bigcup_{n=1}^{\infty} \{1/n\} \times [0,1]$.)

  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.

  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.

  4. if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space. (consider the graph of $sin(1/x)$ in the plane for positive $x$. )

I am interested in this problem in general, especially for the spaces with intrinsic metric.

changed when X is path-connected
Source Link
Ivan Gundyrev
  • 141
  • 1
  • 1
  • 7

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.
  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.
  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.
  4. if $(X,d)$ is path-connected space then $\bar{X}$ ismay be non path-connected space.

I am interested in this problem in general, especially for the spaces with intrinsic metric.

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.
  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.
  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.
  4. if $(X,d)$ is path-connected space then $\bar{X}$ is path-connected space.

I am interested in this problem in general, especially for the spaces with intrinsic metric.

Let $(X,d)$ be a metric space and $(\bar{X},\bar{d})$ its completion. There is a list of topological properties Wikipedia - Topological property

Does anybody know list which of them are retained (inherited) for completion? For example

  1. if $(X,d)$ is locally compact space then $\bar{X}$ may be non-locally compact space.
  2. if $(X,d)$ is separable space then $\bar{X}$ is separable space.
  3. if $(X,d)$ is connected space then $\bar{X}$ is connected space.
  4. if $(X,d)$ is path-connected space then $\bar{X}$ may be non path-connected space.

I am interested in this problem in general, especially for the spaces with intrinsic metric.

Source Link
Ivan Gundyrev
  • 141
  • 1
  • 1
  • 7
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