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Re: What is a Knowledge Graph? CORRECTION

From: Dieter Fensel <dieter.fensel@sti2.at>
Date: Sun, 16 Jun 2019 10:16:41 +0200
To: Patrick J Hayes <phayes@ihmc.us>, "Bradwell (US), Prachant" <prachant.bradwell@boeing.com>
Cc: semantic-web <semantic-web@w3.org>, Chris Harding <chris@lacibus.net>, Paola Di Maio <paoladimaio10@gmail.com>, xyzscy <1047571207@qq.com>
Message-ID: <de344c1c-55aa-eda4-ed5e-ebd5bcd9cb49@sti2.at>
Hi Pat,

thanks for these extremely interesting post. I would like to jump onto 
your summary:

>>>
>>> 5. The semantic nets of the 1970s were, almost univerally, /much/ 
>>> more expressive than knowledge graphs or RDF, or any of the other 
>>> ‘graph’-like modern notations. They typically had ways of encoding 
>>> quantifier scopes, disjunction, negation and sometimes such things 
>>> as modal operators. The grandfather of them all, C.S.Peirce’s 
>>> ‘existential graphs’  had the full expressivity of first-order logic 
>>> in 1885 (implemented as ‘conceptual graphs’ by John Sowa about 90 
>>> years later http://www.jfsowa.com/cg/cgonto.htm). It has been 
>>> downhill from there.
>>>
Indeed, old work on KR was mostly around very expressive Tboxes (and 
Aboxes were just an uninteresting appendix where you put 2-3 facts to 
illustrate your approach). Given the expressivism of that Tboxes it was 
mostly work for the sand box of academic seminars. Turning this work 
from the" Kopf auf die Füsse" is actually the real contribution of the 
recent work on KGs. They come with bizarre large grown Aboxes and with 
extremely simple Tboxes. There may be two major reasons for this:

1) World view: It is very hard to think on useful rules that hold on a 
global scale. I saw trials in recent papers such as "parents and child 
hold same nationality" (does already no hold in my simple case), "wife 
and husband stay in the same city" (...). At University I learnt the 
rule married(a,b) and male(a) implies female(b), and even married(a,b) 
and married(a,c) implies equal(b,c) does not hold on an universal scale. 
Maybe in future married(a,b) implies human(b) may even be invalid. Who 
knows?

2) System view: A system with million of rules and trillions of facts 
will never scale in the foreseeable future of the 21st century. Not even 
during the building and knowledge curation phase.

Therefore, we watch a new systems architecture evolving where extremely 
big (semantic) data lakes are accessed and consolidated by means that 
define a domain and task specific view on them. Kind of heterogeneous 
and distributed micro Tboxes (to make a reference to the idea of micro 
theories in CYC (*). This new view is arising over the last ten years 
based on excellent work of LOD academics and people in industry on 
in-house KGs and it is just in its beginning of releasing its full 
potential. You know it always takes a bit downhill when you leave the 
Ivory tower.

Btw, I think you need at least multi-sets to even cover simple graphs.

(*) with the difference that the KG is not structured by them.
Received on Sunday, 16 June 2019 08:17:10 UTC

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