From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Simple Components (Generic_Directed_Graph) Date: Tue, 31 Oct 2017 16:48:06 +0100 Organization: Aioe.org NNTP Server Message-ID: References: NNTP-Posting-Host: MajGvm9MbNtGBKE7r8NgYA.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 X-Notice: Filtered by postfilter v. 0.8.2 Content-Language: en-US Xref: news.eternal-september.org comp.lang.ada:48688 Date: 2017-10-31T16:48:06+01:00 List-Id: On 2017-10-31 16:07, Victor Porton wrote: > Dmitry A. Kazakov wrote: > > I consider an RDF file. RDF files contain so called "triples" (subject- > predicate-object). Each of the three can be an URI. > > I consider a digraph whose arcs are subject-object (with predicate > expressing the relation "is-subclass-of"). This graph is to store all known > sub-class relations between URIs. It is specifically is there is a path of > "is-subclass-of" relations between any two given URIs. OK, that is a decision tree, a crisp tree in your case. Though usually weighted graphs are used, e.g. in probabilistic and fuzzy, intuitionistic fuzzy trees. In real-life applications such relations are rarely crisp. It is an inference that usually yields a probability or confidence measure of A in B. [In intuitionistic inference it is also other three outcomes A in not B, not A in B, not A in not B.] > Certainly an RDF file can have a subject or object more than once (and even > many times). > > RDF is a mean to store logical (semantic) relations online in a portable > way. A URI may be not a page of the Web, but an abstract object representing > any concept (for example, we can have an URI whose meaning is "cursive font" > or "revolution in Ukraine" or "computer science", just arbitrary, this is > the power of RDF). No, this is weakness. Any = nothing. > Is my solution to use Map to map URIs (you can think of them as strings) to > accesses to empty records (representing graph vertices) a good programming > style? Rather a poor choice. There is no advantage in having copies. One could have them in order to gain something, e.g. performance or design clarity. > I do not need to map a graph vertex into a string, but I need to map a > string into a graph vertex. No, it is a set of vertices implemented as a map because you have trouble using a string for searching the set. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de