diff --git a/properties/P000062.md b/properties/P000062.md index 50c50008d8..687421c5bb 100644 --- a/properties/P000062.md +++ b/properties/P000062.md @@ -13,3 +13,4 @@ Every open cover of $X$ has a countable subcollection whose union is dense in $X - This property is hereditary with respect to clopen sets. - This property is preserved in any coarser topology. +- If a nonempty product space satisfies the property, so does every factor. diff --git a/properties/P000166.md b/properties/P000166.md index 430c93239b..6179bbc085 100644 --- a/properties/P000166.md +++ b/properties/P000166.md @@ -17,4 +17,4 @@ the function space $C_p(X)$ being {P26}. #### Meta-properties - This property is preserved by countable disjoint unions. -- This property is hereditary (use the fact that [Metrizable + Separable => Hereditarily separable](https://topology.pi-base.org/spaces?q=metrizable+%2B+Separable+%2B+%7EHereditarily+separable)). +- This property is hereditary (use the fact that [Metrizable + Separable ⇒ Hereditarily separable](https://topology.pi-base.org/spaces?q=metrizable+%2B+Separable+%2B+%7EHereditarily+separable)). diff --git a/properties/P000206.md b/properties/P000206.md index b3afcfa705..c79651315d 100644 --- a/properties/P000206.md +++ b/properties/P000206.md @@ -26,3 +26,4 @@ to the {{wikipedia:Normal_play_convention}} of combinatorial games. #### Meta-properties - $X$ satisfies this property iff its Kolmogorov quotient $\text{Kol}(X)$ does. +- This property is preserved by arbitrary products and box products. diff --git a/spaces/S000077/README.md b/spaces/S000077/README.md index 2356481c8f..f09d913c9f 100644 --- a/spaces/S000077/README.md +++ b/spaces/S000077/README.md @@ -1,9 +1,11 @@ --- uid: S000077 -name: Michael's product topology +name: Product of Michael line and irrational numbers +aliases: + - Michael's product topology counterexamples_id: 85 refs: - - zb: "0386.54001" + - zb: "0386.54001" name: Counterexamples in Topology --- diff --git a/spaces/S000077/properties/P000006.md b/spaces/S000077/properties/P000006.md deleted file mode 100644 index a042eb8216..0000000000 --- a/spaces/S000077/properties/P000006.md +++ /dev/null @@ -1,7 +0,0 @@ ---- -space: S000077 -property: P000006 -value: true ---- - -Follows as this space is the product of {P000006} spaces. diff --git a/spaces/S000077/properties/P000028.md b/spaces/S000077/properties/P000028.md new file mode 100644 index 0000000000..fd82e6262b --- /dev/null +++ b/spaces/S000077/properties/P000028.md @@ -0,0 +1,7 @@ +--- +space: S000077 +property: P000028 +value: true +--- + +{S63|P28} and {S28|P28}, hence so is their product. diff --git a/spaces/S000077/properties/P000036.md b/spaces/S000077/properties/P000036.md deleted file mode 100644 index 41f7b1dc48..0000000000 --- a/spaces/S000077/properties/P000036.md +++ /dev/null @@ -1,7 +0,0 @@ ---- -space: S000077 -property: P000036 -value: false ---- - -Follows as {S28|P36} and a product is connected if and only if its factors are connected. diff --git a/spaces/S000077/properties/P000050.md b/spaces/S000077/properties/P000050.md new file mode 100644 index 0000000000..48dc58cb6f --- /dev/null +++ b/spaces/S000077/properties/P000050.md @@ -0,0 +1,7 @@ +--- +space: S000077 +property: P000050 +value: true +--- + +{S63|P50} and {S28|P50}, hence so is their product. diff --git a/spaces/S000077/properties/P000051.md b/spaces/S000077/properties/P000051.md deleted file mode 100644 index 906fc7ee27..0000000000 --- a/spaces/S000077/properties/P000051.md +++ /dev/null @@ -1,7 +0,0 @@ ---- -space: S000077 -property: P000051 -value: false ---- - -$X$ contains {S63} as a subspace and {S63|P51}. diff --git a/spaces/S000077/properties/P000062.md b/spaces/S000077/properties/P000062.md new file mode 100644 index 0000000000..3dbab885b8 --- /dev/null +++ b/spaces/S000077/properties/P000062.md @@ -0,0 +1,8 @@ +--- +space: S000077 +property: P000062 +value: false +--- + +If $X$ is {P62}, then so is each of its factors. +However, {S63|P62}. diff --git a/spaces/S000077/properties/P000063.md b/spaces/S000077/properties/P000063.md new file mode 100644 index 0000000000..0e101d7647 --- /dev/null +++ b/spaces/S000077/properties/P000063.md @@ -0,0 +1,7 @@ +--- +space: S000077 +property: P000063 +value: false +--- + +$X$ contains {S63} as a closed subspace and {S63|P63}. diff --git a/spaces/S000077/properties/P000065.md b/spaces/S000077/properties/P000065.md deleted file mode 100644 index 7eb56f37ba..0000000000 --- a/spaces/S000077/properties/P000065.md +++ /dev/null @@ -1,7 +0,0 @@ ---- -space: S000077 -property: P000065 -value: true ---- - -By construction, as $\mathfrak c \cdot \mathfrak c = \mathfrak c$. diff --git a/spaces/S000077/properties/P000139.md b/spaces/S000077/properties/P000139.md new file mode 100644 index 0000000000..8d88a2a713 --- /dev/null +++ b/spaces/S000077/properties/P000139.md @@ -0,0 +1,8 @@ +--- +space: S000077 +property: P000139 +value: false +--- + +If $X$ {P139}, then so does each of its factors. +However, {S28|P139}. diff --git a/spaces/S000077/properties/P000166.md b/spaces/S000077/properties/P000166.md new file mode 100644 index 0000000000..3e73ba027a --- /dev/null +++ b/spaces/S000077/properties/P000166.md @@ -0,0 +1,7 @@ +--- +space: S000077 +property: P000166 +value: true +--- + +The Euclidean topology of $\mathbb R \times (\mathbb R \setminus \mathbb Q)$ is a coarser topology which is {P26} and {P53}. diff --git a/spaces/S000077/properties/P000167.md b/spaces/S000077/properties/P000167.md deleted file mode 100644 index 45ab185caa..0000000000 --- a/spaces/S000077/properties/P000167.md +++ /dev/null @@ -1,7 +0,0 @@ ---- -space: S000077 -property: P000167 -value: false ---- - -$X$ contains a copy of {S28} as a subspace and {S28|P167}. diff --git a/spaces/S000077/properties/P000206.md b/spaces/S000077/properties/P000206.md new file mode 100644 index 0000000000..2fb255b1e0 --- /dev/null +++ b/spaces/S000077/properties/P000206.md @@ -0,0 +1,7 @@ +--- +space: S000077 +property: P000206 +value: true +--- + +{S63|P206} and {S28|P206}, hence so is their product.