Change license, add Makefile, add image caching control

1 files changed, 6 insertions, 3 deletions

diff --git a/source/know/concept/self-energy/index.md b/source/know/concept/self-energy/index.md
index f233466..4120011 100644
--- a/source/know/concept/self-energy/index.md
+++ b/source/know/concept/self-energy/index.md
@@ -204,7 +204,8 @@ that exactly $$2^m m!$$ diagrams at each order are topologically equivalent,
 so we are left with non-equivalent diagrams only.
 Let $$G(b,a) = G_{ba}$$:
 
-{% include image.html file="expansion.png" width="90%" alt="Full expansion of G in Feynman diagrams" %}
+{% include image.html file="expansion.png" width="90%"
+    alt="Full expansion of G in Feynman diagrams" %}
 
 A **reducible diagram** is a Feynman diagram
 that can be cut in two valid diagrams
@@ -215,7 +216,8 @@ At last, we define the **self-energy** $$\Sigma(y,x)$$
 as the sum of all irreducible terms in $$G(b,a)$$,
 after removing the two external lines from/to $$a$$ and $$b$$:
 
-{% include image.html file="definition.png" width="90%" alt="Definition of self-energy" %}
+{% include image.html file="definition.png" width="90%"
+    alt="Definition of the self-energy" %}
 
 Despite its appearance, the self-energy has the semantics of a line,
 so it has two endpoints over which to integrate if necessary.
@@ -234,7 +236,8 @@ Thanks to this recursive structure,
 you can convince youself that $$G(b,a)$$ obeys
 a [Dyson equation](/know/concept/dyson-equation/) involving $$\Sigma(y, x)$$:
 
-{% include image.html file="dyson.png" width="95%" alt="Dyson equation in Feynman diagrams" %}
+{% include image.html file="dyson.png" width="95%"
+    alt="Dyson equation in Feynman diagrams" %}
 
 This makes sense: in the "normal" Dyson equation
 we have a one-body perturbation instead of $$\Sigma$$,