changed (#1438)

Author: Moniker1998

spaces/S000001/README.md

@@ -5,13 +5,14 @@ aliases:
   - Finite Discrete Topology
 counterexamples_id: 1
 refs:
-  - doi: 10.1007/978-1-4612-6290-9
+  - zb: "0386.54001"
     name: Counterexamples in Topology
   - wikipedia: Discrete_space
     name: Discrete Space on Wikipedia
 ---
+
 Let $X=2=\{0,1\}$ be the space containing two points and
 let all subsets of $X$ be open.
 
 Defined as counterexample #1 ("Finite Discrete Topology")
-in {{doi:10.1007/978-1-4612-6290-9}}.
+in {{zb:0386.54001}}.

spaces/S000001/properties/P000052.md

@@ -2,9 +2,6 @@
 space: S000001
 property: P000052
 value: true
-refs:
-- doi: 10.1007/978-1-4612-6290-9
-  name: Counterexamples in Topology
 ---
 
 All subsets of this space are open by definition.

spaces/S000002/README.md

@@ -13,6 +13,7 @@ refs:
   - wikipedia: Discrete_space
     name: Discrete Space on Wikipedia
 ---
+
 Let $X=\omega=\{0,1,2,\dots\}$ be the space containing countably-many
 points and let all subsets of $X$ be open.
 

spaces/S000002/properties/P000052.md

@@ -2,9 +2,6 @@
 space: S000002
 property: P000052
 value: true
-refs:
-- doi: 10.1007/978-1-4612-6290-9
-  name: Counterexamples in Topology
 ---
 
 All subsets of the space are open by definition.

spaces/S000002/properties/P000181.md

@@ -2,9 +2,6 @@
 space: S000002
 property: P000181
 value: true
-refs:
-- doi: 10.1007/978-1-4612-6290-9
-  name: Counterexamples in Topology
 ---
 
-Its cardinality is \(\aleph_0\) by definition.
+By definition.

spaces/S000003/README.md

@@ -5,13 +5,14 @@ aliases:
   - Uncountable Discrete Topology
 counterexamples_id: 3
 refs:
-  - doi: 10.1007/978-1-4612-6290-9 
+  - zb: "0386.54001"
     name: Counterexamples in Topology
   - wikipedia: Discrete_space
     name: Discrete Space on Wikipedia
 ---
+
 Let $X=\mathbb R$ be the set of all real numbers,
 and let all subsets of $X$ be open.
 
 Defined as counterexample #3 ("Uncountable Discrete Topology")
-in {{doi:10.1007/978-1-4612-6290-9}}.
+in {{zb:0386.54001}}.

spaces/S000003/properties/P000052.md

@@ -2,9 +2,6 @@
 space: S000003
 property: P000052
 value: true
-refs:
-- doi: 10.1007/978-1-4612-6290-9
-  name: Counterexamples in Topology
 ---
 
 All subsets of the space are open by definition.

spaces/S000004/README.md

@@ -3,14 +3,15 @@ uid: S000004
 name: Indiscrete Topology on a Two-Point Set
 counterexamples_id: 4
 refs:
-  - doi: 10.1007/978-1-4612-6290-9 
+  - zb: "0386.54001"
     name: Counterexamples in Topology
   - wikipedia: Trivial_topology
     name: Trivial topology on Wikipedia
 ---
+
 Let $X=2=\{0,1\}$ be the space containing two points and
 let only the sets $X$ and $\emptyset$ be open.
 
 
 Defined as counterexample #4 ("Indiscrete Topology")
-in {{doi:10.1007/978-1-4612-6290-9}}.
+in {{zb:0386.54001}}.