docs(undergrad.yaml): recent changes (#6313)

docs/undergrad.yaml

@@ -9,7 +9,7 @@ Linear algebra:
     vector subspace: 'subspace'
     quotient space: 'submodule.quotient'
     sum of subspaces: 'submodule.complete_lattice'
-    direct sum: ''
+    direct sum: '' # this is supposed to be the internal direct sum
     complementary subspaces: 'submodule.exists_is_compl'
     linear independence: 'linear_independent'
     generating sets: 'submodule.span'
@@ -98,15 +98,15 @@ Group Theory:
   Permutation group:
     permutation group of a type: 'equiv.perm'
     decomposition into transpositions: ''
-    decomposition into cycles with disjoint support: ''
+    decomposition into cycles with disjoint support: 'equiv.perm.cycle_factors'
     signature: 'equiv.perm.sign'
     alternating group: ''
   Classical automorphism groups:
     general linear group: 'linear_map.general_linear_group'
     special linear group: 'matrix.special_linear_group'
-    orthogonal group: ''
+    orthogonal group: 'matrix.orthogonal_group '
     special orthogonal group: ''
-    unitary group: ''
+    unitary group: 'matrix.unitary_group'
     special unitary group: ''
   Representation theory of finite groups:
     representations of abelian groups: ''
@@ -366,15 +366,15 @@ Single Variable Complex Analysis:
     radius of convergence: 'formal_multilinear_series.radius'
 #    properties of sums of complex valued series on their disks of convergence: (this is a heading?)
     continuity: 'has_fpower_series_on_ball.continuous_on'
-    differentiability with respect to the complex variable:
+    differentiability with respect to the complex variable: 'has_fpower_series_on_ball.differentiable_on'
     antiderivative:
     complex exponential: 'complex.exp'
     extension of trigonometric functions to the complex plane: 'complex.sin'
     power series expansion of elementary functions:
   Functions on one complex variable:
     holomorphic functions:
     Cauchy-Riemann conditions:
-    line integrals of continuous functions in $\C$:
+    contour integrals of continuous functions in $\C$:
     antiderivatives of a holomorphic function:
     representations of the $\log$ function on $\C$:
     theorem of holomorphic functions under integral domains:
@@ -609,7 +609,7 @@ Distribution calculus:
     Poisson’s formula:
     using convolution and Fourier-Laplace transform to solve one dimensional linear differential equations:
     weak solution of partial derivative equation:
-    elementary solution of the Laplacian:
+    fundamental solution of the Laplacian:
     solving the Laplace equations:
     heat equations:
     wave equations: