Good morning everybody. I’m Federico Cerutti from cardiff university and the title of the course is abstract argumentation and and interfaces to argumentative reasoning which means that we will talk about a lot of things. At the same time I don’t like to go into technical details unless they are necessery so online they should be now a lovely 60 pages handouts of basically just formulas that are not in the slides but the slides are pointing to the handouts so whenever you see definition number here then you can just go on the handouts and look at the real definition. And those slides are derived from the work of a lot of people including people sitting in this audience as well and so a lot of thanks to all of them for their help they provide me with preparing these slides. First of all why should we bother about Dung’s argumentation framework? And, let’s consider that we just have preferences and in a multi-agent system and let’s suppose that’s you have different agents having different pieces of knowledge and then you might have this person that knows that’s a there is no milk in the shop and the milk you have is sour so if you have two choices beer and milk you go for the beer. Easy. And then you have another person that says that there is a coffee machine and fresh coffee in the cup board and beer makes you sick. And you have no other piece of information which means that while there is another alternative and not just be a milk but you can just have coffee for instance and let’s say that you take black coffee not white coffee. Or you can have another agent that says well there is fresh milk in your bag because you went to the shop earlier and you also know that the principal is visiting later on today in their university so you probably better up not drink alcohol so your choice would be zero for beer and one for milk. Now if we take all the three agents views together, well nobody’s winning because one prefers beer, one prefers coffee, one prefers milk. So if instead we start looking inside what each agent knows and we decide to get made putting together everything then we will see that there are some conflicts arising but at the same time you can have a better picture altogether. But how you can handle the conflicts? Because you have, well, you can either drink coffee or you can drink milk, and in this you can just drink one of them let’s assume so. Which means that if you drink milk then you cannot drink coffee. The arrow means an attack so when you have a double arrow means that either one or another but you cannot have both of them at the same time. And at the same time there is another option that is you should drink via which is against coffee and milk and then you have pieces of information coming over supporting or defeating those three options so you have that for one of them beer makes him sick so he might not go and drink beer. But you also know that’s the principle is visiting later on today so you probably better not to drink beer and this is an argument against drinking beer. If you are drinking white coffee you should not drink coffee and you should not drinking milk because there is no making the shop and make you have is sour but then another agent knows that there is a fresh milk in some area of the university so you can just ask and borrow some milk So, known of the three agents altogether you can create conflicts and then the question is what can you do out of it.