From 6686cfa5d5563732dcf036b3b2335eacf26d210c Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Thu, 25 Dec 2025 03:58:46 +0100 Subject: [PATCH 1/5] new theorem --- theorems/T000806.md | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) create mode 100644 theorems/T000806.md diff --git a/theorems/T000806.md b/theorems/T000806.md new file mode 100644 index 000000000..f79a6ac26 --- /dev/null +++ b/theorems/T000806.md @@ -0,0 +1,16 @@ +--- +uid: T000806 +if: + and: + - P000019: true + - P000131: true +then: + P000020: true +refs: + - zb: "1126.54010" + name: When is a compact space sequentially compact? (O. Alas, R. Wilson) +--- + +Established as corollary 2.2 in {{zb:1126.54010}}. + +In fact, theorem 2.1 shows slightly more generally that if $hL(X) < \mathfrak{t}$ and $X$ is countably compact, then $X$ is sequentially compact. Here $hL(X)$ is the hereditary Lindelof number and $\mathfrak{t}$ is the tower number, where $\omega_1\leq \mathfrak{t}\leq \mathfrak{c}$. From eae46ba53ff82da1c72c8aee0e45e82026d50992 Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Fri, 26 Dec 2025 14:30:02 +0100 Subject: [PATCH 2/5] compromising --- theorems/T000806.md | 2 -- 1 file changed, 2 deletions(-) diff --git a/theorems/T000806.md b/theorems/T000806.md index f79a6ac26..619fcadb5 100644 --- a/theorems/T000806.md +++ b/theorems/T000806.md @@ -12,5 +12,3 @@ refs: --- Established as corollary 2.2 in {{zb:1126.54010}}. - -In fact, theorem 2.1 shows slightly more generally that if $hL(X) < \mathfrak{t}$ and $X$ is countably compact, then $X$ is sequentially compact. Here $hL(X)$ is the hereditary Lindelof number and $\mathfrak{t}$ is the tower number, where $\omega_1\leq \mathfrak{t}\leq \mathfrak{c}$. From 1a02e17f99d9c78acaadf1fb1ea5918d1016a325 Mon Sep 17 00:00:00 2001 From: Moniker1998 Date: Sat, 10 Jan 2026 11:18:40 +0100 Subject: [PATCH 3/5] updated with references and so on --- theorems/T000806.md | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/theorems/T000806.md b/theorems/T000806.md index 619fcadb5..42d3f357a 100644 --- a/theorems/T000806.md +++ b/theorems/T000806.md @@ -9,6 +9,8 @@ then: refs: - zb: "1126.54010" name: When is a compact space sequentially compact? (O. Alas, R. Wilson) + - mo: 506776 + name: Proof of Alas and Wilson that countably compact hereditarily Lindelof spaces are sequentially compact --- -Established as corollary 2.2 in {{zb:1126.54010}}. +Established as corollary 2.2 of theorem 2.1 in {{zb:1126.54010}}. Note that the proof of theorem 2.1 contains errors which need corrections. These are discussed in {{mo:506776}}. From 2232cd63af00802ee7987c18757fe530c4c084f0 Mon Sep 17 00:00:00 2001 From: Moniker1998 <88507423+Moniker1998@users.noreply.github.com> Date: Sat, 10 Jan 2026 22:47:11 +0100 Subject: [PATCH 4/5] Update theorems/T000806.md Co-authored-by: Patrick Rabau <70125716+prabau@users.noreply.github.com> --- theorems/T000806.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/theorems/T000806.md b/theorems/T000806.md index 42d3f357a..402f6aba0 100644 --- a/theorems/T000806.md +++ b/theorems/T000806.md @@ -13,4 +13,4 @@ refs: name: Proof of Alas and Wilson that countably compact hereditarily Lindelof spaces are sequentially compact --- -Established as corollary 2.2 of theorem 2.1 in {{zb:1126.54010}}. Note that the proof of theorem 2.1 contains errors which need corrections. These are discussed in {{mo:506776}}. +Established as Corollary 2.2 of Theorem 2.1 in {{zb:1126.54010}}. Note that the proof of Theorem 2.1 contains errors which need corrections. These are discussed in {{mo:506776}}. From 5d271212e67c41959dc90a327886796249f7aebb Mon Sep 17 00:00:00 2001 From: Moniker1998 <88507423+Moniker1998@users.noreply.github.com> Date: Sat, 10 Jan 2026 23:11:08 +0100 Subject: [PATCH 5/5] Update theorems/T000806.md Co-authored-by: Patrick Rabau <70125716+prabau@users.noreply.github.com> --- theorems/T000806.md | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/theorems/T000806.md b/theorems/T000806.md index 402f6aba0..76d706f00 100644 --- a/theorems/T000806.md +++ b/theorems/T000806.md @@ -13,4 +13,6 @@ refs: name: Proof of Alas and Wilson that countably compact hereditarily Lindelof spaces are sequentially compact --- -Established as Corollary 2.2 of Theorem 2.1 in {{zb:1126.54010}}. Note that the proof of Theorem 2.1 contains errors which need corrections. These are discussed in {{mo:506776}}. +Established as Corollary 2.2 of Theorem 2.1 in {{zb:1126.54010}} +(available [here](https://topology.nipissingu.ca/tp/reprints/v29/tp29201.pdf)). +Note that the proof of Theorem 2.1 contains errors which need corrections. These are discussed in {{mo:506776}}.