working on readme

README.md

@@ -8,7 +8,27 @@ The purpose of the library is to generate the Dirichlet-to-Neumann (Steklov-Poin
 
 We consider a Neumann boundary value problem for the Laplace equation in 3D,
 
-<img src="manual/omega.png" alt="Omega"/>
+<img src="manual/bvp.png" alt="BVP"> with the compatibility condition <img src="manual/compat.png" alt="compatibility condition">.
+
+The domain is decomposed into a set of plane triangles
+
+<img src="manual/omega.png" alt="Omega"/>.
+
+The heatDtN library provides a Dirichlet-to-Neumann operator
+
+<img src="manual/sp.png" alt="Steklov-Poincaré"/>
+
+discretized via the Galerkin boundary element method as
+
+<img src="manual/sph.png" alt="Steklov-Poincaré"/>
+
+or in its non-symmetric form as
+
+<img src="manual/sphn.png" alt="Steklov-Poincaré"/>.
+
+The individual matrices composing the operator are given as
+
+
 
 ## Compilation