I am searching tutorials and wikipedias to understand what is the differnece between OWLs, RDFs, TTLs. As I have understood all these are metadata (or ontologies) but what exactly is the essential difference between them? Thanks...
https://www.w3.org/RDF/ https://en.wikipedia.org/wiki/Web_Ontology_Language
OWL and RDF are knowledge representation languages, TTL, or Turtle, is simply one syntax to express OWL or RDF ontologies (i.e., sets of axioms) in a text file.
Roughly speaking, the main difference between OWL and RDF is that OWL has more constructs to express logical axioms. OWL is also layered with multiple complexity levels, depending on which ones of the constructs you use. As a consequence of this layering, automatic reasoning in OWL has different performance implications than reasoning in RDF.
The semantics of RDF is largely contained in the semantics of OWL (indeed, most RDF constructs are included in OWL) but not all of RDF is included in all the OWL (and the more elaborate OWL 2) layers.