Em Qua, Outubro 22, 2008 5:05 pm, Frank Wales escreveu: > Miguel P. Monteiro wrote: >> From what I could learn, both abstraction and generalisation seem to be ways >> to "navigate" through hierarchical structures of concepts. These are useful to compress >> information in an efficient way: a concept at one level can subsume all >> concepts at >> lower levels (I suppose this is abstraction). In addition, different levels >> of the >> hierarchy support different inferences. An inference about a concept at one >> level does not necessarily apply to a concept at a more abstract level. This seems to be >> related to generalisation. > > Perhaps I've misunderstood, but I think you have these the wrong way around. > > The way I think about abstraction and generalization is that they are two independent axes, one running from detailed to abstract, and one running from specific to general.
I've been thinking abstraction and generalization as traversals over the same axis in opposite directions, with abstraction going from detailed to abstract. Perhaps I should take a second look at generalisation... Thanks for pointing this out. My source for the distinction is Czarnecki's thesis, section 2.3.7: http://www.prakinf.tu-ilmenau.de/~czarn/diss/diss.pdf > So, going from talking about 'Frank Wales's anatomy' to talking about 'human anatomy' means you're talking more generally, but not necessarily in any less detail than before. That would be generalisation, because information increased: from applying it to a single specific case, it is next applied to a larger set. > Going from 'Frank Wales' to 'Frank Wales's > blood pressure' means you're throwing away all the details irrelevant to the > task at hand, and in doing so have become more abstract, but not necessarily any less specific than before. That looks the inverse of abstraction to me (concretisation), because it results in more detail - blood pressure. I'm assuming we're not leaving aside all previous detail about Frank Wales. However, if we forget all details about Frank Wales not related to Frank Wales's blood pressure, that may be abstraction again. mpm > Does that accord with what you've learnt? > > (This is where I find out I'm the only person in the world who thinks this way about these things. As usual.) > -- > Frank Wales [EMAIL PROTECTED] > -- Miguel P. Monteiro | cell phone +351 96 700 35 45 Departamento de Informatica | Phone +351 21 294 8536 ext. 10708 Faculdade Ciencias e Tecnol.| Fax: +351 21 294 8541 Universidade Nova de Lisboa | URL: http://ctp.di.fct.unl.pt/~mpm 2829-516 Caparica, PORTUGAL | Skype: miguel.p.monteiro
