diff --git a/judge/markdown.py b/judge/markdown.py
index ba594c1..5260f85 100644
--- a/judge/markdown.py
+++ b/judge/markdown.py
@@ -6,7 +6,7 @@ from pymdownx import superfences
 
 
 EXTENSIONS = [
-    # "pymdownx.arithmatex",
+    "pymdownx.arithmatex",
     "pymdownx.magiclink",
     "pymdownx.betterem",
     "pymdownx.details",
@@ -25,6 +25,9 @@ EXTENSIONS = [
 ]
 
 EXTENSION_CONFIGS = {
+    "pymdownx.arithmatex": {
+        "generic": True,
+    },
     "pymdownx.superfences": {
         "custom_fences": [
             {
@@ -83,7 +86,6 @@ def markdown(value, lazy_load=False):
         value, extensions=extensions, extension_configs=EXTENSION_CONFIGS
     )
 
-    soup = BeautifulSoup(html, "html.parser")
     html = bleach.clean(html, tags=ALLOWED_TAGS, attributes=ALLOWED_ATTRS)
 
     if not html:
diff --git a/judge/signals.py b/judge/signals.py
index 74ae833..7987bbd 100644
--- a/judge/signals.py
+++ b/judge/signals.py
@@ -46,7 +46,6 @@ def problem_update(sender, instance, **kwargs):
     cache.delete_many(
         [
             make_template_fragment_key("submission_problem", (instance.id,)),
-            make_template_fragment_key("problem_feed", (instance.id,)),
             "problem_tls:%s" % instance.id,
             "problem_mls:%s" % instance.id,
         ]
diff --git a/resources/katex_config.js b/resources/katex_config.js
index 0a18883..a87b1ee 100644
--- a/resources/katex_config.js
+++ b/resources/katex_config.js
@@ -1,17 +1,13 @@
-window.KatexOptions = {
-    delimiters: [
-        {left: '$$', right: '$$', display: true},
-        {left: '$', right: '$', display: false},
-        {left: '\\[', right: '\\]', display: true},
-        {left: "\\(", right: "\\)", display: false},
-        {left: "\\begin{equation}", right: "\\end{equation}", display: true},
-        {left: "\\begin{align}", right: "\\end{align}", display: true},
-        {left: "\\begin{alignat}", right: "\\end{alignat}", display: true},
-        {left: "\\begin{gather}", right: "\\end{gather}", display: true},
-        {left: "\\begin{CD}", right: "\\end{CD}", display: true},
-    ],
-    throwOnError : false
-};
 window.renderKatex = (elem=document.body) => {
- 	renderMathInElement(elem, window.KatexOptions);
+  var maths = document.querySelectorAll('.arithmatex'),
+          tex;
+  console.log(maths);
+  for (var i = 0; i < maths.length; i++) {
+    tex = maths[i].textContent || maths[i].innerText;
+    if (tex.startsWith('\\(') && tex.endsWith('\\)')) {
+      katex.render(tex.slice(2, -2), maths[i], {'displayMode': false, 'throwOnError': false});
+    } else if (tex.startsWith('\\[') && tex.endsWith('\\]')) {
+      katex.render(tex.slice(2, -2), maths[i], {'displayMode': true, 'throwOnError': false});
+    }
+  }
 }
\ No newline at end of file
diff --git a/templates/katex-load.html b/templates/katex-load.html
index 017e574..d87ce4d 100644
--- a/templates/katex-load.html
+++ b/templates/katex-load.html
@@ -1,4 +1,4 @@
 <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.16.9/dist/katex.min.css" integrity="sha384-n8MVd4RsNIU0tAv4ct0nTaAbDJwPJzDEaqSD1odI+WdtXRGWt2kTvGFasHpSy3SV" crossorigin="anonymous">
 <script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.9/dist/katex.min.js" integrity="sha384-XjKyOOlGwcjNTAIQHIpgOno0Hl1YQqzUOEleOLALmuqehneUG+vnGctmUb0ZY0l8" crossorigin="anonymous"></script>
 <script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.9/dist/contrib/auto-render.min.js" integrity="sha384-+VBxd3r6XgURycqtZ117nYw44OOcIax56Z4dCRWbxyPt0Koah1uHoK0o4+/RRE05" crossorigin="anonymous"
-  onload="renderMathInElement(document.body, window.KatexOptions);"></script>
\ No newline at end of file
+  onload="renderKatex();"></script>
\ No newline at end of file