Changes to Stratified Lecture

• 2021-11-16 08:47:30 UTC (Hans Georg Schaathun): Some notes from last lecture
• 2021-11-10 13:15:17 UTC (Hans Georg Schaathun): friday exercise
• 2021-11-09 18:36:14 UTC (Hans Georg Schaathun): notes
• 2021-11-09 17:51:41 UTC (Hans Georg Schaathun): stubs