added todos to README.md

Author: kollerlukas

README.md

@@ -1 +1,9 @@
 # Formalising Theory of Approximating the Travelling-Salesman Problem
+
+## TODO
+- [x] formalize and proof correct Double-Tree algorithm (`./DoubleTree.thy`)
+- [x] formalize and proof correct Christofides-Serdyukov algorithm (`./ChristofidesSerdyukov.thy`)
+- [ ] (?) connect Prim formalization (finish adaptor `./MSTPrimAdaptor.thy`)
+- [ ] (?) formalize and proof correct algroithm for Eulerian Tour (`./Eulerian.thy`)
+- [ ] (?) formalize Multi-graphs by encoding Multi-graphs in normal-simple graphs (`./MultiGraph.thy`)
+- [ ] proof MAXSNP-hardness of metric TSP