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On blank nodes

Published on Nov 25, 20117152 Views

Blank nodes are defined in RDF as ‘existential variables’ in the same way that has been used before in mathematical logic. However, evidence suggests that actual usage of RDF does not follow this de

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Chapter list

On Blank Nodes00:00
How are blank nodes defined?00:30
How many times has Federer won the French Open?01:26
In RDF, blank nodes are anonymous existential variables02:37
Careful with the terminology: names, labels and the like03:34
In RDF, blank nodes are anonymous existential variables - 104:08
In RDF, blank nodes are anonymous existential variables - 204:28
In RDF, blank nodes are anonymous existential variables - 304:37
In RDF, blank nodes are anonymous existential variables - 404:54
In RDF, blank nodes are anonymous existential variables - 505:06
In RDF, blank nodes are anonymous existential variables - 605:25
In RDF, blank nodes are anonymous existential variables - 705:42
In RDF, blank nodes are anonymous existential variables - 805:53
Blank nodes are not used as NULLs - 106:02
Blank nodes are not used as NULLs - 207:08
Blank nodes are not used as NULLs - 307:09
Blank nodes are not the same as NULLs - 107:48
Blank nodes are not the same as NULLs - 208:02
In practice, blank nodes are used as constants - 108:32
In practice, blank nodes are used as constants - 209:09
as local/structural constructs in data structures09:57
as default names - 111:33
as default names - 211:51
as default names - 312:02
Not all the normative uses are common in practice12:15
SPARQL considers blank nodes as different constants - 113:07
SPARQL considers blank nodes as different constants - 213:29
SPARQL considers blank nodes as different constants - 313:38
SPARQL considers blank nodes as different constants - 413:57
SPARQL considers blank nodes as different constants - 514:35
Blank nodes in The Wild: size - 114:52
Blank nodes in The Wild: size - 215:37
Blank nodes: structure - 116:34
Blank nodes: structure - 217:14
Blank nodes: structure - 317:31
Blank nodes: structure - 418:41
Blank nodes in The Wild: plenty of "good" graphs19:19
The outlier: a graph with "blank treewidth" of 7 - 119:49
The outlier: a graph with "blank treewidth" of 7 - 220:15
The outlier: a graph with "blank treewidth" of 7 - 320:55
The outlier: a graph with "blank treewidth" of 7 - 421:12
How to guarantee a tree-structure for blank nodes21:34
What if I want to get rid of blank nodes - 122:27
What if I want to get rid of blank nodes - 224:20
Standardizing the process with a Skolemization scheme24:49
Towards a Skolemization scheme - 125:36
Towards a Skolemization scheme - 226:05
Towards a Skolemization scheme - 326:11
Towards a Skolemization scheme - 426:31
Towards a Skolemization scheme - 526:45
Summary27:50