Bootstrap ancestry
in [UK Mac]
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From: Rowland McDonnell on 21 Jun 2010 13:46 Richard Tobin <richard(a)cogsci.ed.ac.uk> wrote: > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > >I had to look up `transitive closure' when it was first used in this > >thread. > > > >And I still don't get it. Wikip says this: > > > >"In mathematics, a binary relation R over a set X is transitive if > >whenever an element a is related to an element b, and b is in turn > >related to an element c, then a is also related to c." > > Example: "ancestor" is the transitive closure of "parent". > > Given (ordered) pairs of people A and B, Okay - first hiccup: `ordered' pairs? What ordering? Where's it specified? I can imagine a set of pairs of people -- yep, no trouble. The set contains nothing but pairs, fine. But that'll be pairs like this: A and A' B and B' C and C' .. .. .. or so I'd write it. So you've lost me at the first hurdle. (Look, I always wanted to be an *experimental* physicist, at least after I'd found out I found heavy maths /heavy/...) > some are in the relation "B > is the parent of A". I can dig a set of people - but what's this `A' and `B' general specifier? > "Parent" isn't a transitive relation, because > B being the parent of A and C being the parent of B doesn't imply > that C is the parent of A. Yeah, that's straightforward English usage, that is. > The relation "ancestor" is what you get if you keep applying "parent". Erm? Lost you there. > It's called the closure because you go on until you don't get any > new elements - the resulting set is closed. Umm - yeah, but `go on with' what, exactly? > It's transitive in that > if B is an ancestor of A and C is an ancestor of B, then C is an > ancestor of A. If B is an ancestor of A and C is an ancestor of B, then C is an ancestor of C - is an /example/ of the property of transitivity. Yes. I don't see anything else there, though. > >btw, I don't reckon that your definition of `ancestors of a program' is > >a valid one. Surely it's like saying that any food I eat is my > >ancestor? > > Yes, it's just like that. The food you eat isn't your ancestor, but > it seems like a reasonable metaphor. Reasonable metaphor for using a programming language (eating food) to write a new program (growing my body), is how I was looking at it. Rowland. -- Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org Sorry - the spam got to me http://www.mag-uk.org http://www.bmf.co.uk UK biker? Join MAG and the BMF and stop the Eurocrats banning biking
From: Richard Tobin on 21 Jun 2010 15:41 In article <1jkg905.1x29vqz1q95ar0N%real-address-in-sig(a)flur.bltigibbet.invalid>, Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: >> Given (ordered) pairs of people A and B, > >Okay - first hiccup: `ordered' pairs? What ordering? Where's it >specified? "Ordered" just means that the pair A,B is different from the pair B,A. >> some are in the relation "B is the parent of A". >I can dig a set of people - but what's this `A' and `B' general >specifier? E.g. B = Margarent Thatcher, A = Mark Thatcher. Just an example. >> The relation "ancestor" is what you get if you keep applying "parent". > >Erm? Lost you there. Your ancestors are the people you get to by taking your parents, their parents, their parents, ... >> It's called the closure because you go on until you don't get any >> new elements - the resulting set is closed. > >Umm - yeah, but `go on with' what, exactly? Go on applying the parent relation. Of course, when I say "go on", I'm describing the natural way of finding the ancestors. The rigorous definition of transitive closure would be declarative, rather than procedural. >> Yes, it's just like that. The food you eat isn't your ancestor, but >> it seems like a reasonable metaphor. >Reasonable metaphor for using a programming language (eating food) to >write a new program (growing my body), is how I was looking at it. As I've probably remarked before, "The Origin of Consciousness in the Breakdown of the Bicameral Mind" is good on metaphors, even if you don't accept its main thesis. -- Richard
From: Pd on 21 Jun 2010 16:03 Richard Tobin <richard(a)cogsci.ed.ac.uk> wrote: > As I've probably remarked before, "The Origin of Consciousness in > the Breakdown of the Bicameral Mind" is good on metaphors, even if > you don't accept its main thesis. It was in this august forum not more than a dozen days ago that I propounded language as almost a necessity for consciousness, so at least on that point I agree with Jaynes. -- Pd
From: Woody on 21 Jun 2010 17:26 Woody <usenet(a)alienrat.co.uk> wrote: > Ian McCall <ian(a)eruvia.org> wrote: > >> We being the general marketplace, not particular individuals within >> it. Transputers never really caught on in a big way, and all was said >> to be down to optimising compilers and languages for multithreading >> and getting developers to understand it properly. > > I so wanted the atari transputer workstation. I loved the idea of > occam > and it seemed such a logical design for the future of computing. Of > course viewing it from a software point of view rather than a world > view > didn't help. Was too young to realise (actually care) that the world > didn't want flashy computers, they wanted to write rubbishy > powerpoints > instead. And on that subject <http://www.theregister.co.uk/2010/06/21/amiga_x1000/> -- Woody
From: John DoH on 21 Jun 2010 17:27
In article <1jkckl8.15bubau1pgc4i0N%real-address-in-sig(a)flur.bltigibbet.invalid>, real-address-in-sig(a)flur.bltigibbet.invalid (Rowland McDonnell) wrote: > jim <jim(a)magrathea.plus.com> wrote: > > > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote: > > > > > "Every program has a branching and converging bootstrap ancestry." > > > > > > I've written code without any ancestry at all. > > > > I doubt that. Not unless you've developed your own CPU from first > > principles. > > Eh? Don't be silly. The patterning of the code I produced is what had > no ancestry, is what I mean. Then say what you mean, only you yourself can understand Rowlandese [snip bollocks] > > Rowland. -- "Telling someone to kill themselves is not harmful: it's merely me expressing an opinion. You try to drive people to suicide - that's evil. My behaviour is perfectly okay; your behaviour is evil - plain and simple evil." Rowland McDonnell - 9th. Mar. 2009 |