From 3e0ac67340dab2db87004c6d4dae882500c442b3 Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Tue, 9 Sep 2025 11:55:56 +0200 Subject: [PATCH 1/9] add three new theorems --- theorems/T000788.md | 9 +++++++++ theorems/T000789.md | 15 +++++++++++++++ theorems/T000790.md | 15 +++++++++++++++ 3 files changed, 39 insertions(+) create mode 100644 theorems/T000788.md create mode 100644 theorems/T000789.md create mode 100644 theorems/T000790.md diff --git a/theorems/T000788.md b/theorems/T000788.md new file mode 100644 index 0000000000..817e4b4989 --- /dev/null +++ b/theorems/T000788.md @@ -0,0 +1,9 @@ +--- +uid: T000788 +if: + P000110: true +then: + P000117: true +--- + +Let $(\mathcal{U}_n)$ be development for $X$. Since every developable space is subparacompact, there exist a $\sigma$-locally finite closed refinement $\mathcal{V}_n$ of $\mathcal{U}_n$ for each $n$. Then $\mathcal{N} = \bigcup_n \mathcal{V}_n$ is $\sigma$-locally finite, and if $x\in W$ with $W$ open, then there is $n$ with $\text{St}(x, \mathcal{U}_n)\subseteq W$, and so $\text{St}(x, \mathcal{V}_n)\subseteq \text{St}(x, \mathcal{U}_n)\subseteq W$. Since $\mathcal{V}_n$ is a cover, it follows that there is $V\in\mathcal{V}_n$ with $x\in V\subseteq W$. So $\mathcal{N}$ is a $\sigma$-locally finite closed network. diff --git a/theorems/T000789.md b/theorems/T000789.md new file mode 100644 index 0000000000..61df8ee7c5 --- /dev/null +++ b/theorems/T000789.md @@ -0,0 +1,15 @@ +--- +uid: T000789 +if: + and: + - P000011: true + - P000028: true + - P000118: true +then: + P000121: true +refs: + - doi: 10.1002/mana.19700450103 + name: A Metrization Theorem (P. O'Meara) +--- + +We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. diff --git a/theorems/T000790.md b/theorems/T000790.md new file mode 100644 index 0000000000..229ee9977b --- /dev/null +++ b/theorems/T000790.md @@ -0,0 +1,15 @@ +--- +uid: T000790 +if: + and: + - P000011: true + - P000130: true + - P000118: true +then: + P000121: true +refs: + - doi: 10.1002/mana.19700450103 + name: A Metrization Theorem (P. O'Meara) +--- + +We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. From 81de33fce1d0cbdea987c407766193336592f287 Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Tue, 9 Sep 2025 12:38:24 +0200 Subject: [PATCH 2/9] replaced obsolete theorems --- theorems/T000516.md | 13 +++++++------ theorems/T000517.md | 13 +++++++------ theorems/T000789.md | 15 --------------- theorems/T000790.md | 15 --------------- 4 files changed, 14 insertions(+), 42 deletions(-) delete mode 100644 theorems/T000789.md delete mode 100644 theorems/T000790.md diff --git a/theorems/T000516.md b/theorems/T000516.md index cd68d60dec..a442db20b7 100644 --- a/theorems/T000516.md +++ b/theorems/T000516.md @@ -2,13 +2,14 @@ uid: T000516 if: and: - - P000179: true - - P000028: true + - P000011: true + - P000028: true + - P000118: true then: - P000053: true + P000121: true refs: -- zb: "0148.16701" - name: $\aleph_0$-spaces (E. Michael) + - doi: 10.1002/mana.19700450103 + name: A Metrization Theorem (P. O'Meara) --- -See result (B) in {{zb:0148.16701}} (). +We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. diff --git a/theorems/T000517.md b/theorems/T000517.md index aa9a67c328..26f10c1d4b 100644 --- a/theorems/T000517.md +++ b/theorems/T000517.md @@ -2,13 +2,14 @@ uid: T000517 if: and: - - P000179: true - - P000023: true + - P000011: true + - P000130: true + - P000118: true then: - P000053: true + P000121: true refs: -- zb: "0148.16701" - name: $\aleph_0$-spaces (E. Michael) + - doi: 10.1002/mana.19700450103 + name: A Metrization Theorem (P. O'Meara) --- -See result (C) in {{zb:0148.16701}} (). +We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. diff --git a/theorems/T000789.md b/theorems/T000789.md deleted file mode 100644 index 61df8ee7c5..0000000000 --- a/theorems/T000789.md +++ /dev/null @@ -1,15 +0,0 @@ ---- -uid: T000789 -if: - and: - - P000011: true - - P000028: true - - P000118: true -then: - P000121: true -refs: - - doi: 10.1002/mana.19700450103 - name: A Metrization Theorem (P. O'Meara) ---- - -We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. diff --git a/theorems/T000790.md b/theorems/T000790.md deleted file mode 100644 index 229ee9977b..0000000000 --- a/theorems/T000790.md +++ /dev/null @@ -1,15 +0,0 @@ ---- -uid: T000790 -if: - and: - - P000011: true - - P000130: true - - P000118: true -then: - P000121: true -refs: - - doi: 10.1002/mana.19700450103 - name: A Metrization Theorem (P. O'Meara) ---- - -We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. From 6b5dce33802456dd503883861c320a19663cd446 Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Fri, 12 Sep 2025 09:01:05 +0200 Subject: [PATCH 3/9] added Kolmogorov --- properties/P000028.md | 1 + properties/P000118.md | 5 +++++ properties/P000178.md | 5 +++++ 3 files changed, 11 insertions(+) diff --git a/properties/P000028.md b/properties/P000028.md index 5bae15f1c6..1b517f5979 100644 --- a/properties/P000028.md +++ b/properties/P000028.md @@ -16,3 +16,4 @@ Defined on page 7 of {{doi:10.1007/978-1-4612-6290-9}}. - This property is hereditary. - A space that is locally {P28} (every point has a neighborhood with the property) has the property. +- $X$ satisfies this property iff its Kolmogorov quotient $\text{Kol}(X)$ does. diff --git a/properties/P000118.md b/properties/P000118.md index f41503d578..043685d5b9 100644 --- a/properties/P000118.md +++ b/properties/P000118.md @@ -11,3 +11,8 @@ A space with a $\sigma$-locally finite $k$-network. A family $\mathcal N$ of subsets of $X$ is called a *$k$-network* if for every compact set $K$ and open set $U$ in $X$ with $K\subseteq U$, there exists a finite $\mathcal{N}^* \subseteq \mathcal{N}$ with $K \subseteq \bigcup\mathcal{N}^* \subseteq U$. The family $\mathcal N$ is *$\sigma$-locally finite* if it is a countable union of locally finite families. See for example Definition 2.1 in {{doi:10.1016/j.topol.2015.05.085}}. + +---- +#### Meta-properties + +- $X$ satisfies this property iff its Kolmogorov quotient $\text{Kol}(X)$ does. diff --git a/properties/P000178.md b/properties/P000178.md index 3c223d81ab..0b00ec98e4 100644 --- a/properties/P000178.md +++ b/properties/P000178.md @@ -11,3 +11,8 @@ refs: A space that is {P5} and {P118}. The notion was introduced in {{doi:10.1090/S0002-9939-1971-0276919-3}}. + +---- +#### Meta-properties + +- The Kolmogorov quotient $\text{Kol}(X)$ is {P178} iff $X$ is {P11} and {P118}. From 03d3aa9c3afbfeea46df54a8ed30e665322f6a4f Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Tue, 30 Dec 2025 21:55:07 +0100 Subject: [PATCH 4/9] changed theorems to allow redundancy --- theorems/T000516.md | 7 +++---- theorems/T000517.md | 7 +++---- theorems/T000820.md | 12 ++++++++++++ theorems/T000821.md | 12 ++++++++++++ 4 files changed, 30 insertions(+), 8 deletions(-) create mode 100644 theorems/T000820.md create mode 100644 theorems/T000821.md diff --git a/theorems/T000516.md b/theorems/T000516.md index a442db20b7..591caad474 100644 --- a/theorems/T000516.md +++ b/theorems/T000516.md @@ -2,14 +2,13 @@ uid: T000516 if: and: - - P000011: true + - P000178: true - P000028: true - - P000118: true then: - P000121: true + P000053: true refs: - doi: 10.1002/mana.19700450103 name: A Metrization Theorem (P. O'Meara) --- -We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. +The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. diff --git a/theorems/T000517.md b/theorems/T000517.md index 26f10c1d4b..37ee7bec6a 100644 --- a/theorems/T000517.md +++ b/theorems/T000517.md @@ -2,14 +2,13 @@ uid: T000517 if: and: - - P000011: true + - P000178: true - P000130: true - - P000118: true then: - P000121: true + P000053: true refs: - doi: 10.1002/mana.19700450103 name: A Metrization Theorem (P. O'Meara) --- -We can assume $X$ is a {P178} by taking Komogorov quotient. The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. +Follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. diff --git a/theorems/T000820.md b/theorems/T000820.md new file mode 100644 index 0000000000..86f8c2cb43 --- /dev/null +++ b/theorems/T000820.md @@ -0,0 +1,12 @@ +--- +uid: T000820 +if: + and: + - P000011: true + - P000028: true + - P000118: true +then: + P000121: true +--- + +Follows from {T516} by taking Komogorov quotient. diff --git a/theorems/T000821.md b/theorems/T000821.md new file mode 100644 index 0000000000..b4859cac69 --- /dev/null +++ b/theorems/T000821.md @@ -0,0 +1,12 @@ +--- +uid: T000821 +if: + and: + - P000011: true + - P000023: true + - P000118: true +then: + P000121: true +--- + +Follows from {T517} by taking Komogorov quotient. From 3a2bbb0512d578a32b18a21dec747d644802f227 Mon Sep 17 00:00:00 2001 From: Moniker1998 <88507423+Moniker1998@users.noreply.github.com> Date: Wed, 31 Dec 2025 09:29:23 +0100 Subject: [PATCH 5/9] Update theorems/T000820.md Co-authored-by: Patrick Rabau <70125716+prabau@users.noreply.github.com> --- theorems/T000820.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/theorems/T000820.md b/theorems/T000820.md index 86f8c2cb43..6c23ea1d33 100644 --- a/theorems/T000820.md +++ b/theorems/T000820.md @@ -9,4 +9,4 @@ then: P000121: true --- -Follows from {T516} by taking Komogorov quotient. +Follows from {T516} by taking Kolmogorov quotient. From 5a2741144292da8082d7db9d15f5db90ba291a37 Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Wed, 31 Dec 2025 11:53:57 +0100 Subject: [PATCH 6/9] rewrote T516 and T517 --- theorems/T000516.md | 2 +- theorems/T000517.md | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/theorems/T000516.md b/theorems/T000516.md index 591caad474..2ca9ab56d8 100644 --- a/theorems/T000516.md +++ b/theorems/T000516.md @@ -11,4 +11,4 @@ refs: name: A Metrization Theorem (P. O'Meara) --- -The theorem follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. +Established in theorem 1 of {{doi:10.1002/mana.19700450103}}, see remarks after definition 2. diff --git a/theorems/T000517.md b/theorems/T000517.md index 37ee7bec6a..ebe5f63375 100644 --- a/theorems/T000517.md +++ b/theorems/T000517.md @@ -11,4 +11,4 @@ refs: name: A Metrization Theorem (P. O'Meara) --- -Follows from a more general result for $r$-spaces in {{doi:10.1002/mana.19700450103}}. +Established in theorem 1 of {{doi:10.1002/mana.19700450103}}, see remarks after definition 2. From 78b61257bd51c6a862a197c14a824ee0d3837ceb Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Thu, 1 Jan 2026 06:37:55 +0100 Subject: [PATCH 7/9] changed --- properties/P000132.md | 5 +++++ theorems/T000821.md | 8 ++++---- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/properties/P000132.md b/properties/P000132.md index 5290f3e9f5..9b3fc7ee59 100644 --- a/properties/P000132.md +++ b/properties/P000132.md @@ -18,3 +18,8 @@ Equivalently, a space in which every open set is an $F_\sigma$ set (a countable Defined on page 162 of {{doi:10.1007/978-1-4612-6290-9}}. Note: A $G_\delta$ space is sometimes called a "perfect space" (Exercise 1.5.H(a) in {{zb:0684.54001}}). Not to be be confused with a space that is a "perfect" in the sense of "perfect set" (= a set equal to its derived set = a closed set that is dense-in-itself), that is, a space without isolated point. See the discussion in . + +---- +#### Meta-properties + +- $X$ satisfies this property iff its Kolmogorov quotient $\text{Kol}(X)$ does. diff --git a/theorems/T000821.md b/theorems/T000821.md index b4859cac69..f3fe13c0b1 100644 --- a/theorems/T000821.md +++ b/theorems/T000821.md @@ -2,11 +2,11 @@ uid: T000821 if: and: - - P000011: true - P000023: true - - P000118: true + - P000134: true + - P000132: true then: - P000121: true + P000028: true --- -Follows from {T517} by taking Komogorov quotient. +Follows from {T503} by taking Kolmogorov quotient. From cb1639058e325fe748f461fb3921ee20a41bd0e6 Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Thu, 1 Jan 2026 07:27:39 +0100 Subject: [PATCH 8/9] changed --- theorems/T000517.md | 12 +++++------- theorems/T000821.md | 12 ------------ 2 files changed, 5 insertions(+), 19 deletions(-) delete mode 100644 theorems/T000821.md diff --git a/theorems/T000517.md b/theorems/T000517.md index ebe5f63375..d825cec6ff 100644 --- a/theorems/T000517.md +++ b/theorems/T000517.md @@ -2,13 +2,11 @@ uid: T000517 if: and: - - P000178: true - - P000130: true + - P000023: true + - P000134: true + - P000132: true then: - P000053: true -refs: - - doi: 10.1002/mana.19700450103 - name: A Metrization Theorem (P. O'Meara) + P000028: true --- -Established in theorem 1 of {{doi:10.1002/mana.19700450103}}, see remarks after definition 2. +Follows from {T503} by taking Kolmogorov quotient. diff --git a/theorems/T000821.md b/theorems/T000821.md deleted file mode 100644 index f3fe13c0b1..0000000000 --- a/theorems/T000821.md +++ /dev/null @@ -1,12 +0,0 @@ ---- -uid: T000821 -if: - and: - - P000023: true - - P000134: true - - P000132: true -then: - P000028: true ---- - -Follows from {T503} by taking Kolmogorov quotient. From 54979287f1845e88fef5b912844b891807e87011 Mon Sep 17 00:00:00 2001 From: Moniker1998 <88507423+Moniker1998@users.noreply.github.com> Date: Thu, 1 Jan 2026 07:47:30 +0100 Subject: [PATCH 9/9] Update theorems/T000788.md Co-authored-by: Patrick Rabau <70125716+prabau@users.noreply.github.com> --- theorems/T000788.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/theorems/T000788.md b/theorems/T000788.md index 817e4b4989..3f9b4bcefa 100644 --- a/theorems/T000788.md +++ b/theorems/T000788.md @@ -6,4 +6,4 @@ then: P000117: true --- -Let $(\mathcal{U}_n)$ be development for $X$. Since every developable space is subparacompact, there exist a $\sigma$-locally finite closed refinement $\mathcal{V}_n$ of $\mathcal{U}_n$ for each $n$. Then $\mathcal{N} = \bigcup_n \mathcal{V}_n$ is $\sigma$-locally finite, and if $x\in W$ with $W$ open, then there is $n$ with $\text{St}(x, \mathcal{U}_n)\subseteq W$, and so $\text{St}(x, \mathcal{V}_n)\subseteq \text{St}(x, \mathcal{U}_n)\subseteq W$. Since $\mathcal{V}_n$ is a cover, it follows that there is $V\in\mathcal{V}_n$ with $x\in V\subseteq W$. So $\mathcal{N}$ is a $\sigma$-locally finite closed network. +Let $(\mathcal{U}_n)$ be development for $X$. Since {T730}, there exist a $\sigma$-locally finite closed refinement $\mathcal{V}_n$ of $\mathcal{U}_n$ for each $n$. Then $\mathcal{N} = \bigcup_n \mathcal{V}_n$ is $\sigma$-locally finite, and if $x\in W$ with $W$ open, then there is $n$ with $\text{St}(x, \mathcal{U}_n)\subseteq W$, and so $\text{St}(x, \mathcal{V}_n)\subseteq \text{St}(x, \mathcal{U}_n)\subseteq W$. Since $\mathcal{V}_n$ is a cover, it follows that there is $V\in\mathcal{V}_n$ with $x\in V\subseteq W$. So $\mathcal{N}$ is a $\sigma$-locally finite network.