Combinatorics terms

docs/Public/Math/Sets/k-subset.md

@@ -0,0 +1,7 @@
+A *k-subset* of a [[set]] $S$ is a [[subset]] of $S$ with [[cardinality]] $k$.
+
+Example: The $3$*-subset* of $S = \{1, 2, 3, 4\}$ are
+
+$$
+\{1, 2, 3\}, \{1, 2, 4\}, \{1, 3, 4\}, \{2, 3, 4\}
+$$

docs/Public/Math/Sets/set.md

@@ -1,5 +1,5 @@
 *See:* [[Set theory]] 
 
-A *set* is a collection of "things": elements, members, objects, etc. [^1]
+A *set* is a (unordered) collection of "things": elements, members, objects, etc. [^1]
 
 [^1]: https://matthbeck.github.io/papers/aop.noprint.pdf

docs/Public/Math/Sets/subset.md

@@ -1,10 +1,11 @@
 A *subset* is a [[set]] which all the elements are contained in another set. 
+Another way, "Every element in $A$ is in $B$".
 
 $A$ is a *subset* of $B$ means:
 $$
 \text{If }x\in A, \text{ then } x\in B
 $$
 We write:
 $$
-a\subseteq B
+A\subseteq B
 $$

docs/Public/Software/AI/time series.md

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+*Time series* is a [[machine learning]] technique that forecasts target values based solely on a known history of target values. [^1]
+
+[^1]: https://docs.oracle.com/en/database/oracle/machine-learning/oml4sql/21/dmcon/time-series.html#GUID-0D6954B9-9D66-42E2-A62F-F3FFE84B827E

docs/Public/Software/Tools/Appearance/colors.md

@@ -17,5 +17,7 @@ jzky colorway:
 	- Light Cyan: 35ceb3
 - Accent: af9a91
 	- Light Accent: e1c6bb
+- Black 0c0a0a
+	- Light Black: 241e1e