diff --git a/physica-manual.pdf b/physica-manual.pdf
index a85543e..58dbd5b 100644
Binary files a/physica-manual.pdf and b/physica-manual.pdf differ
diff --git a/physica-manual.typ b/physica-manual.typ
index ee2270a..d3d6146 100644
--- a/physica-manual.typ
+++ b/physica-manual.typ
@@ -165,7 +165,7 @@ All symbols need to be used in *math mode* `$...$`.
   [`TT`],
   [],
   [`v^TT, A^TT` #sym.arrow $v^TT, A^TT$],
-  [transpose, also see\ @matrix-tranpose],
+  [transpose, also see\ @matrix-transpose],
 
   [`vectorbold(`_content_`)`],
   [`vb`],
@@ -234,7 +234,7 @@ All symbols need to be used in *math mode* `$...$`.
   [`TT`],
   [],
   [`v^TT, A^TT` #sym.arrow $v^TT, A^TT$],
-  [transpose, also see\ @matrix-tranpose],
+  [transpose, also see\ @matrix-transpose],
 
   [#builtin([`mat(`...`)`])],
   [],
@@ -607,8 +607,8 @@ Functions: `differential(`\*_args_, \*\*_kwargs_`)`, abbreviated as `dd(`...`)`.
   column-gutter: 2em,
 
   [
-    *(1)* #hl(`dd(f), dd(x,y)`) \
-    $ dd(f), dd(x,y) $
+    *(1)* #hl(`dd(f), f(x,y) dd(x,y)`) \
+    $ dd(f), f(x,y) dd(x,y) $
   ],
   [
     *(2)* #hl(`dd(x,3), dd(f,[k]), dd(f,[k],d:delta)`) \
@@ -785,7 +785,7 @@ In the default font, the Typst built-in symbol `planck.reduce` $planck.reduce$ l
   [$ i hbar pdv(,t) psi = -frac(hbar^2, 2m) laplacian psi $],
 )
 
-=== Matrix transpose with superscript T <matrix-tranpose>
+=== Matrix transpose with superscript T <matrix-transpose>
 
 #v(1em)
 
diff --git a/physica.typ b/physica.typ
index 7f3ff2a..470946f 100644
--- a/physica.typ
+++ b/physica.typ
@@ -482,7 +482,9 @@
       arr.push($dsym#var$)
     }
   }
-  $#arr.join(prod)$
+  // Wrap in op(...) to give it smart spacing, just like Typst's built-in "dif"
+  // symbol. For example, there should be a space in the middle of "f(x) dx".
+  $op(#arr.join(prod))$
 }
 #let dd = differential
 
diff --git a/typst.toml b/typst.toml
index 79ba0dc..c666474 100644
--- a/typst.toml
+++ b/typst.toml
@@ -8,9 +8,10 @@ keywords = [
   "physics", "mathematics", "brace", "set", "product", "evaluate", "restrict",
   "integral", "gradient", "divergence", "curl", "vector", "field", "laplacian",
   "matrix", "determinant", "diagonal", "identity", "Jacobian", "Hessian",
-  "Dirac", "braket", "differential", "derivative", "partial", "dv", "odv",
-  "pdv", "Planck", "hbar", "tensor", "isotope", "signal", "electromagnetism",
-  "mechanics", "quantum", "relativity", "imaginary", "notation",
+  "transpose", "Dirac", "braket", "differential", "derivative", "partial",
+  "dv", "odv", "pdv", "Planck", "hbar", "tensor", "isotope", "signal",
+  "electromagnetism", "mechanics", "quantum", "relativity", "imaginary",
+  "notation",
 ]
 compiler = "0.10.0"
 exclude = ["*.pdf", "*.py"]