vault backup: 2026-04-08 15:10:32

vault backup: 2026-04-08 13:00:12
vault backup: 2026-04-08 10:52:50
2026-04-08 15:10:32 +02:00 · 2026-04-08 13:00:12 +02:00 · 2026-04-08 10:52:50 +02:00 · 2026-04-08 10:46:13 +02:00
12 changed files with 244 additions and 121 deletions
--- a/.obsidian/snippets/matugen.css
+++ b/.obsidian/snippets/matugen.css
@@ -6,113 +6,113 @@
 .theme-dark, .theme-light {

    /* ── Material You RGB helpers ──────────────────────────── */
-    --mat-bg-rgb:             32, 15, 13;
-    --mat-surface-rgb:        32, 15, 13;
-    --mat-on-surface-rgb:     253, 219, 215;
-    --mat-primary-rgb:        255, 180, 172;
-    --mat-on-primary-rgb:     105, 0, 7;
+    --mat-bg-rgb:             19, 18, 29;
+    --mat-surface-rgb:        19, 18, 29;
+    --mat-on-surface-rgb:     228, 224, 240;
+    --mat-primary-rgb:        195, 192, 255;
+    --mat-on-primary-rgb:     29, 0, 165;

    /* ── Core Backgrounds ──────────────────────────────────── */
-    --background-primary:           #200f0d;
-    --background-primary-alt:       #200f0d;
-    --background-secondary:         #291715;
-    --background-secondary-alt:     #2d1b19;
+    --background-primary:           #13121d;
+    --background-primary-alt:       #13121d;
+    --background-secondary:         #1b1a25;
+    --background-secondary-alt:     #1f1e29;

    /* ── Titlebar ──────────────────────────────────────────── */
-    --titlebar-background:          #200f0d;
-    --titlebar-background-focused:  #291715;
-    --titlebar-text-color:          #fddbd7;
+    --titlebar-background:          #13121d;
+    --titlebar-background-focused:  #1b1a25;
+    --titlebar-text-color:          #e4e0f0;

    /* ── Borders & Dividers ────────────────────────────────── */
-    --background-modifier-border:         #5d3f3c;
-    --background-modifier-border-focus:   #ae8884;
-    --background-modifier-border-hover:   #ae8884;
+    --background-modifier-border:         #464557;
+    --background-modifier-border-focus:   #918fa3;
+    --background-modifier-border-hover:   #918fa3;

    /* ── Text Colors ───────────────────────────────────────── */
-    --text-normal:      #fddbd7;
-    --text-muted:       #e7bdb8;
-    --text-faint:       #ae8884;
-    --text-on-accent:   #690007;
-    --text-selection:   rgba(255, 180, 172, 0.25);
+    --text-normal:      #e4e0f0;
+    --text-muted:       #c7c4da;
+    --text-faint:       #918fa3;
+    --text-on-accent:   #1d00a5;
+    --text-selection:   rgba(195, 192, 255, 0.25);

    /* ── Accent & Interactive ──────────────────────────────── */
-    --interactive-accent:           #ffb4ac;
-    --interactive-accent-hover:     #de1521;
-    --interactive-accent-rgb:       255, 180, 172;
-    --text-accent:                  #ffb4ac;
-    --text-accent-hover:            #de1521;
+    --interactive-accent:           #c3c0ff;
+    --interactive-accent-hover:     #3c24f6;
+    --interactive-accent-rgb:       195, 192, 255;
+    --text-accent:                  #c3c0ff;
+    --text-accent-hover:            #3c24f6;

    /* ── Hover & Active Modifiers ──────────────────────────── */
    --background-modifier-hover:          rgba(var(--mat-on-surface-rgb), 0.06);
    --background-modifier-active-hover:   rgba(var(--mat-primary-rgb), 0.15);
-    --background-modifier-success:        #0075b9;
+    --background-modifier-success:        #a32200;
    --background-modifier-error:          #93000a;
    --background-modifier-error-hover:    #ffb4ab;

    /* ── Obsidian Color Scale (--color-base-XX) ────────────── */
-    --color-base-00:    #200f0d;
-    --color-base-05:    #200f0d;
-    --color-base-10:    #1a0a08;
-    --color-base-20:    #291715;
-    --color-base-25:    #2d1b19;
-    --color-base-30:    #392523;
-    --color-base-35:    #452f2d;
-    --color-base-40:    #5d3f3c;
-    --color-base-50:    #ae8884;
-    --color-base-60:    #e7bdb8;
-    --color-base-70:    #fddbd7;
-    --color-base-100:   #fddbd7;
+    --color-base-00:    #13121d;
+    --color-base-05:    #13121d;
+    --color-base-10:    #0d0d17;
+    --color-base-20:    #1b1a25;
+    --color-base-25:    #1f1e29;
+    --color-base-30:    #292934;
+    --color-base-35:    #34343f;
+    --color-base-40:    #464557;
+    --color-base-50:    #918fa3;
+    --color-base-60:    #c7c4da;
+    --color-base-70:    #e4e0f0;
+    --color-base-100:   #e4e0f0;

    /* ── Semantic Colors ───────────────────────────────────── */
    --color-red:        #ffb4ab;
-    --color-orange:     #98cbff;
-    --color-yellow:     #ffb4ac;
-    --color-green:      #0075b9;
-    --color-cyan:       #8b1919;
-    --color-blue:       #ffb4ac;
-    --color-purple:     #ffb4ac;
-    --color-pink:       #98cbff;
+    --color-orange:     #ffb4a3;
+    --color-yellow:     #c3c0ff;
+    --color-green:      #a32200;
+    --color-cyan:       #3e3a96;
+    --color-blue:       #c3c0ff;
+    --color-purple:     #c3c0ff;
+    --color-pink:       #ffb4a3;

    /* ── Headings ──────────────────────────────────────────── */
-    --h1-color:     #ffb4ac;
-    --h2-color:     #ffb4ac;
-    --h3-color:     #ffb4ac;
-    --h4-color:     #98cbff;
-    --h5-color:     #e7bdb8;
-    --h6-color:     #ae8884;
+    --h1-color:     #c3c0ff;
+    --h2-color:     #c3c0ff;
+    --h3-color:     #c3c0ff;
+    --h4-color:     #ffb4a3;
+    --h5-color:     #c7c4da;
+    --h6-color:     #918fa3;

    /* ── Links ─────────────────────────────────────────────── */
-    --link-color:           #ffb4ac;
-    --link-color-hover:     #ffffff;
-    --link-external-color:  #98cbff;
-    --link-unresolved-color: #ae8884;
+    --link-color:           #c3c0ff;
+    --link-color-hover:     #faf6ff;
+    --link-external-color:  #ffb4a3;
+    --link-unresolved-color: #918fa3;

    /* ── Tags ──────────────────────────────────────────────── */
-    --tag-color:            #ffffff;
-    --tag-background:       #de1521;
-    --tag-border-color:     #ffb4ac;
-    --tag-color-hover:      #690007;
-    --tag-background-hover: #ffb4ac;
+    --tag-color:            #faf6ff;
+    --tag-background:       #3c24f6;
+    --tag-border-color:     #c3c0ff;
+    --tag-color-hover:      #1d00a5;
+    --tag-background-hover: #c3c0ff;

    /* ── Checkboxes ────────────────────────────────────────── */
-    --checkbox-color:           #ffb4ac;
-    --checkbox-color-hover:     #de1521;
-    --checkbox-border-color:    #ae8884;
-    --checkbox-marker-color:    #690007;
+    --checkbox-color:           #c3c0ff;
+    --checkbox-color-hover:     #3c24f6;
+    --checkbox-border-color:    #918fa3;
+    --checkbox-marker-color:    #1d00a5;

    /* ── Code Blocks ───────────────────────────────────────── */
-    --code-background:  #291715;
-    --code-normal:      #fddbd7;
-    --code-comment:     #ae8884;
-    --code-function:    #ffb4ac;
+    --code-background:  #1b1a25;
+    --code-normal:      #e4e0f0;
+    --code-comment:     #918fa3;
+    --code-function:    #c3c0ff;
    --code-important:   #ffb4ab;
-    --code-keyword:     #ffb4ac;
-    --code-operator:    #98cbff;
-    --code-property:    #e7bdb8;
-    --code-punctuation: #5d3f3c;
-    --code-string:      #98cbff;
+    --code-keyword:     #c3c0ff;
+    --code-operator:    #ffb4a3;
+    --code-property:    #c7c4da;
+    --code-punctuation: #464557;
+    --code-string:      #ffb4a3;
    --code-tag:         #ffb4ab;
-    --code-value:       #ffb4ac;
+    --code-value:       #c3c0ff;

    /* ── Scrollbar ─────────────────────────────────────────── */
    --scrollbar-thumb-bg:           rgba(var(--mat-on-surface-rgb), 0.12);
@@ -121,16 +121,16 @@

    /* ── Inputs ────────────────────────────────────────────── */
    --input-shadow: none;
-    --input-shadow-hover: 0 0 0 2px #ae8884;
+    --input-shadow-hover: 0 0 0 2px #918fa3;

    /* ── Graph View ────────────────────────────────────────── */
-    --graph-node:           #ffb4ac;
-    --graph-node-unresolved: #ae8884;
-    --graph-node-focused:   #ffffff;
-    --graph-node-tag:       #ffb4ac;
-    --graph-node-attachment: #98cbff;
-    --graph-line:           #5d3f3c;
-    --graph-background:     #200f0d;
+    --graph-node:           #c3c0ff;
+    --graph-node-unresolved: #918fa3;
+    --graph-node-focused:   #faf6ff;
+    --graph-node-tag:       #c3c0ff;
+    --graph-node-attachment: #ffb4a3;
+    --graph-line:           #464557;
+    --graph-background:     #13121d;

 }

--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -13,15 +13,44 @@
            "state": {
              "type": "markdown",
              "state": {
-                "file": "00 Inbox/29593940 - Formal Languages.md",
+                "file": "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593852 - Strings.md",
                "mode": "source",
                "source": false
              },
              "icon": "lucide-file",
-              "title": "29593940 - Formal Languages"
+              "title": "29593852 - Strings"
+            }
+          },
+          {
+            "id": "e179fd2c20f4067e",
+            "type": "leaf",
+            "state": {
+              "type": "markdown",
+              "state": {
+                "file": "00 Inbox/29593975 - Regular Expressions.md",
+                "mode": "source",
+                "source": false
+              },
+              "icon": "lucide-file",
+              "title": "29593975 - Regular Expressions"
+            }
+          },
+          {
+            "id": "1e58a188bb5d367b",
+            "type": "leaf",
+            "state": {
+              "type": "markdown",
+              "state": {
+                "file": "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593952 - Regular Languages.md",
+                "mode": "source",
+                "source": false
+              },
+              "icon": "lucide-file",
+              "title": "29593952 - Regular Languages"
            }
          }
-        ]
+        ],
+        "currentTab": 1
      }
    ],
    "direction": "vertical"
@@ -182,14 +211,19 @@
      "darlal-switcher-plus:Open Symbols for the active editor": false
    }
  },
-  "active": "140d404d9b2faf63",
+  "active": "e179fd2c20f4067e",
  "lastOpenFiles": [
-    "00 Inbox/29593952 - Regular Languages.md",
-    "00 Inbox/29593940 - Formal Languages.md",
-    "00 Inbox/29593935 - Kleene.md",
+    "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593952 - Regular Languages.md",
+    "00 Inbox/29593975 - Regular Expressions.md",
+    "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593940 - Formal Languages.md",
+    "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593852 - Strings.md",
+    "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593958 - Kleene star of languages.md",
+    "30 Library/29593962 - atfl-st2026-l02-finite-representation-of-languages-full.pdf",
+    "30 Library/normalize_name.sh",
+    "30 Library/atfl-st2026-l02-finite-representation-of-languages-full.pdf",
+    "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593935 - Kleene.md",
    "30 Library/29593895 - atfl-st2026-l01-formal-languages-full.pdf",
-    "00 Inbox/29593852 - Strings.md",
-    "00 Inbox/29593929 - Alphabets.md",
+    "10 Courses/02 - SoSe 2026/Automatentheorie und formale Sprachen/29593929 - Alphabets.md",
    "30 Library/29592593 - ET_II_Folien_gesamt_020426.pdf",
    "30 Library/29592593 - 29592593 - ET_II_Folien_gesamt_020426.pdf",
    "30 Library/atfl-st2026-l01-formal-languages-full.pdf",
@@ -214,12 +248,7 @@
    "00 Inbox/29593226 - ET_II_Folien_gesamt_020426.pdf.md",
    "10 Courses/02 - SoSe 2026/ET II/29592722 - Zeitabhängige Größen.md",
    "10 Courses/02 - SoSe 2026/ET II/29592709 - Klausur.md",
-    "10 Courses/02 - SoSe 2026/ET II/29592729 - Kirchhoffsche Gesetze.md",
-    "00 Inbox/29593224 - 29593223 - 29593223 - Elektrotechnik II.md",
    "20 Atlas",
-    "30 Library/ET_II_Folien_gesamt_020426.pdf",
-    "30 Library/d6d88eed747e389e597d2a19bb868ee6?cid=4b45b3a6f32c35a6d9ca5b1b07b760de",
-    "30 Library/wget-log",
    "10 Courses/01 - WiSe 2025_26/ET/images/beispiel_knotenregel.png"
  ]
 }
--- a/Inbox/29593952
+++ b/Inbox/29593952
@@ -1,20 +0,0 @@
---
-created: 2026-04-08 10:32
-course: "[[29593850 - Automationtheory]]"
-topic: languages
-related: "[[29593940 - Formal Languages]]"
-type: lecture
-status: 🔴
-tags:
-  - university
---
-## 📌 Summary
-
-> [!abstract]
-> 
-
---
-
-## 📝 Content
-
-A language $L$ that can be described by a regular expression $r$ (i. e. $L(r) = L$) is called _regular_.
--- a/Expressions.md
+++ b/Expressions.md
@@ -0,0 +1,33 @@
+---
+created: 2026-04-08 10:55
+course: "[[29593850 - Automationtheory]]"
+topic: languages
+related: "[[29593940 - Formal Languages#Finite representation of languages]]"
+type: lecture
+status: 🔴
+tags:
+  - university
+---
+## 📌 Summary
+
+> [!abstract]
+> 
+
+---
+
+## 📝 Content
+
+A _regular expression_ $r$ over an alphabet $Sigma$ is defined recursively:
+- $emptyset, epsilon$ and each $a in Sigma$ are regular expression, which represent the Languages $L(emptyset) = emptyset, L(epsilon) = {epsilon}$ and $L(a) = {a}$
+- If $r$ and $s$ are regular expressions then these are also regular expressions:
+	- $(r + s)$ with $L(r + s) = L(r) union L(s)$
+	- $(r s)$ with $L(r s) = L(r)L(s)$
+	- $r^*$ with $L(r^*) = L(r)^*$
+
+
+> [!EXAMPLE]
+> The language $L$ over $Sigma = {a, b}$ containing the substring $a b$ is regular, since it can be expressed using the regular expression
+> $r = (a +b)^* a b (a + b)^*$
+
+## Equivalence of regular expressions
+Two regular expressiosn $r$ and $s$ are _equivalent_ ($r eq.triple s$ or $r hat(eq) s$) if thy generate the same language ($L(r) eq L(s)$).
--- a/2026/Automatentheorie
+++ b/2026/Automatentheorie
--- a/2026/Automatentheorie
+++ b/2026/Automatentheorie
--- a/2026/Automatentheorie
+++ b/2026/Automatentheorie
--- a/2026/Automatentheorie
+++ b/2026/Automatentheorie
@@ -49,10 +49,6 @@ The $n^"th"$  power of the language $L subset.eq Sigma^*$ over alphabet $Sigma$
 **Goal:** Represent a language using _finite_ information
 ### Using set notation
 $S = {a^n b^m bar n, m >= 0} = {epsilon, a, b, "aa", "ab", ...}$
-> This is very inefficient.
+> This is limited in practice.

 ### Using regular expressions
-A _regular expression_ $r$ over an alphabet $Sigma$ is defined recursively:
- $emptyset, epsilon$ and each $a in Sigma$ are regular expression, which represent the Languages $L(emptyset) = emptyset, L(epsilon) = {epsilon}$ and $L(a) = {a}$
- If $r$ and $s$ are regular expressions then
-	- $(r+s)$
--- a/2026/Automatentheorie
+++ b/2026/Automatentheorie
@@ -0,0 +1,24 @@
+---
+created: 2026-04-08 10:32
+course: "[[29593850 - Automationtheory]]"
+topic: languages
+related: "[[29593940 - Formal Languages]]"
+type: lecture
+status: 🔴
+tags:
+  - university
+---
+## 📌 Summary
+
+> [!abstract]
+> 
+
+---
+
+## 📝 Content
+
+A language $L$ that can be described by a [[29593975 - Regular Expressions|Regular Expression]] $r$ (i. e. $L(r) = L$) is called _regular_.
+
+> [!WARNING]
+> There a several important languages that **cannot** be described by a regular expression.
+> <mark style="background: #CACFD9A6;">(proof later)</mark>
--- a/2026/Automatentheorie
+++ b/2026/Automatentheorie
@@ -0,0 +1,25 @@
+---
+created: 2026-04-08 10:38
+course: "[[29593850 - Automationtheory]]"
+topic: kleene
+related: "[[29593940 - Formal Languages]]"
+type: lecture
+status: 🔴
+tags:
+  - university
+---
+## 📌 Summary
+
+> [!abstract]
+> 
+
+---
+
+## 📝 Content
+
+The _Kleene star_ $L^*$ of a language $L subset Sigma^*$ is the set of all strings (including the empty string $epsilon$) that can be generated by arbitrary concatenation of strings in the language, that is
+> $L^* := union.big_(n >= 0) L^n$
+
+> [!EXAMPLE]
+> For $L = {01}$ one has $L^* = {epsilon, 01, 0101, 010101, ...}$
+> $= {(01)^n bar n >= 0}$
--- a/atfl-st2026-l02-finite-representation-of-languages-full.pdf
+++ b/atfl-st2026-l02-finite-representation-of-languages-full.pdf
--- a/Library/normalize_name.sh
+++ b/Library/normalize_name.sh
@@ -0,0 +1,36 @@
+#!/bin/bash
+
+# Check if a filename was provided
+if [ -z "$1" ]; then
+    echo "Usage: $0 <filename>"
+    exit 1
+fi
+
+TARGET="$1"
+
+# Check if the file actually exists
+if [ ! -f "$TARGET" ]; then
+    echo "Error: File '$TARGET' not found."
+    exit 1
+fi
+
+# Get creation time (%W).
+# Note: Returns 0 or '-' if the filesystem doesn't support birth time.
+BTIME=$(stat -c %W "$TARGET")
+
+# Fallback to last modification time (%Y) if birth time is unavailable
+if [ "$BTIME" -eq 0 ] || [ "$BTIME" == "-" ]; then
+    BTIME=$(stat -c %Y "$TARGET")
+fi
+
+# Calculate the minute-based timestamp (equivalent to Math.floor(ms / 60000))
+# Since stat returns seconds, we divide by 60.
+FORMATTED_DATE=$(( BTIME / 60 ))
+
+# Define the new name
+NEW_NAME="${FORMATTED_DATE} - ${TARGET}"
+
+# Perform the rename
+mv "$TARGET" "$NEW_NAME"
+
+echo "Renamed: '$TARGET' -> '$NEW_NAME'"
Author	SHA1	Message	Date
Jan Meyer	33843cd0e6	vault backup: 2026-04-08 15:10:32	2026-04-08 15:10:32 +02:00
Jan Meyer	8bcf049ced	vault backup: 2026-04-08 13:00:12	2026-04-08 13:00:12 +02:00
Jan Meyer	d21c72e4e7	vault backup: 2026-04-08 10:52:50	2026-04-08 10:52:50 +02:00
Jan Meyer	46bb25c44a	vault backup: 2026-04-08 10:46:13	2026-04-08 10:46:13 +02:00