Difference between RDF Containers and Collections? -

-

i have read book

the difference between containers , collections lies in fact containers open (i.e., new members may added through additional rdf statements) , collections may closed.

i don't understand difference clearly. says no new members can added collection. if change value of last rdf:rest property rdf:nil _:xyz , add

_:xyz rdf:first <ex:aaa> . _:xyz rdf:rest rdf:nil .

i able add new member _:xyz. why collections closed?

the key difference in container, can continue add new items, asserting new rdf triples. in collection, first have remove statement before can add new items.

this important difference in particular rdf reasoning. it's important because rdf reasoning employs open world assumption (owa), which, put simply, states because fact not known, not mean can assume fact untrue.

if apply principle container, , ask question "how many items container have", answer must "i don't know", because there no way determine how many unknown items might in container. however, if have collection, have explicit marker last item, can certainty how many items collection contains - there can no unknown additional items.


Comments

Post a Comment

Popular posts from this blog

javascript - Count length of each class -

-
i have below code in this fiddle . html <span class="myname">john smith</span> <span class="myname">john smith</span> <span class="myname">john smith</span> <span class="myname">john smith</span> <span class="myname">john smith</span> <span class="myname">john smith</span> javascript $('.myname').each(function(){ var text = $(this).html().split(' '), len = text.length, test = $(this).val().length, result = []; console.log('outside: ' + test); for( var = 0; < len; i++ ) { result[i] = '<span class="name-'+[i]+'" >' + text[i] + '</span>'; console.log('inside: ' + test); } $(this).html(result.join(' ')); console.log('after
Read more

What design pattern is this code in Javascript? -

-
this question has answer here: why write “.call(this)” @ end of javascript anonymous function? [duplicate] 4 answers what kind of design pattern , significance of using closure? (function(){ // code here }).call(this); edit then difference between above code , following this keyword still refer same object in both ways. (function(){ // code here })(); thats invoked function expression. more info here: http://benalman.com/news/2010/11/immediately-invoked-function-expression/ the purpose run code while protecting scope (so variables declared within don't leak out global scope. update call sets value of this function being applied on. without it, value set window object, there set outer scope.
Read more

hadoop - Restrict secondarynamenode to be installed and run on any other node in the cluster -

-
i have have cloudera cdh3u4 cluster setup. have secondarynamenode daemon running on 1 of nodes. i have ensure user has root access node on cluster (for example, datanode not have other daemons running) should not able start instance of secondarynamenode daemon on node (thereby having 2 secondarynamenodes on cluster) how can achieve this? thanks in advance. add property hdfs-site.xml namedfs.secondary.http.address valuesecondarynamenode-host address or ip:50090
Read more