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24-434: An XML document has an information set if it is well-formed and satisfies the namespace constraints. There is no requirement for an XML document to be valid in order to have an information set. An information set can contain up to eleven different types of information items: XML was initially developed without a formal definition of its infoset. This was only formalised by later work beginning in 1999, first published as

48-406: A necessary consequence of its premises. An argument that is not valid is said to be "invalid". An example of a valid (and sound ) argument is given by the following well-known syllogism : What makes this a valid argument is not that it has true premises and a true conclusion. Validity is about the tie in relationship between the two premises the necessity of the conclusion. There needs to be

72-410: A document are correctly formed and follow XML guidelines, then a document is considered as well formed." An XML processor that encounters a violation of the well-formedness rules is required to report such errors and to cease normal processing. This policy, occasionally referred to as draconian , stands in notable contrast to the behavior of programs that process HTML , which are designed to produce

96-421: A false conclusion, and it is equally valid: No matter how the universe might be constructed, it could never be the case that these arguments should turn out to have simultaneously true premises but a false conclusion. The above arguments may be contrasted with the following invalid one: In this case, the conclusion contradicts the deductive logic of the preceding premises, rather than deriving from it. Therefore,

120-562: A form that makes it impossible for the premises to be true and the conclusion nevertheless to be false . It is not required for a valid argument to have premises that are actually true, but to have premises that, if they were true, would guarantee the truth of the argument's conclusion. Valid arguments must be clearly expressed by means of sentences called well-formed formulas (also called wffs or simply formulas ). The validity of an argument can be tested, proved or disproved, and depends on its logical form . In logic, an argument

144-444: A formula is valid if all such interpretations make it true. An inference is valid if all interpretations that validate the premises validate the conclusion. This is known as semantic validity . In truth-preserving validity, the interpretation under which all variables are assigned a truth value of 'true' produces a truth value of 'true'. In a false-preserving validity, the interpretation under which all variables are assigned

168-480: A reasonable result even in the presence of severe markup errors in the spirit of Postel's law ("Be conservative in what you send; be liberal in what you accept"). The concept of a well-formed document allows for a better understanding of the fundamental construction of XML. It helps to clarify XML beyond the typical sense of it. For example, while most XML Document Type Definitions utilize left and right angle brackets as content delimiters, strictly speaking this

192-449: A relationship established between the premises i.e., a middle term between the premises. If you just have two unrelated premises there is no argument. Notice some of the terms repeat: men is a variation man in premises one and two, Socrates and the term mortal repeats in the conclusion. The argument would be just as valid if both premises and conclusion were false. The following argument is of the same logical form but with false premises and

216-573: A separate W3C Working Draft at the end of December that year. Infoset recommendation Second Edition was adopted on 4 February, 2004. If a 2.0 version of the XML standard is ever published, it is likely that this would absorb the Infoset recommendation as an integral part of that standard. Infoset augmentation or infoset modification refers to the process of modifying the infoset during schema validation, for example by adding default attributes. The augmented infoset

240-412: A well-formed document, rules must be established about the declaration and treatment of entities. Tags are case sensitive , with attributes delimited with quotation marks. Empty elements have rules established. Overlapping tags invalidate a document. Ideally, a well-formed document conforms to the design goals of XML. Other key syntax rules provided in the specification include: A valid XML document

264-403: Is a set of related statements expressing the premises (which may consists of non-empirical evidence, empirical evidence or may contain some axiomatic truths) and an necessary conclusion based on the relationship of the premises. An argument is valid if and only if it would be contradictory for the conclusion to be false if all of the premises are true. Validity does not require the truth of

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288-410: Is called the post-schema-validation infoset, or PSVI . Infoset augmentation is somewhat controversial, with claims that it is a violation of modularity and tends to cause interoperability problems, since applications get different information depending on whether or not validation has been performed. Infoset augmentation is supported by XML Schema but not RELAX NG . Typically, XML Information Set

312-434: Is defined in the XML specification as a well-formed XML document which also conforms to the rules of a Document Type Definition (DTD). According to JavaCommerce.com XML tutorial, "Well formed XML documents simply markup pages with descriptive tags. You don't need to describe or explain what these tags mean. In other words a well formed XML document does not need a DTD, but it must conform to the XML syntax rules. If all tags in

336-415: Is not a necessity (though a delimiter should be terse and concise). The left and right angle bracket codes are a convention, albeit clear and distinctive, not an absolute requirement. The concept of well-formed document also allows for the comprehension of the abstract nature of XML. In reality, there is no such thing as XML. Rather, XML is a principle that represents a set of behaviors and practices. It

360-434: Is not affected by the truth of the premise or the truth of the conclusion. The following deduction is perfectly valid: The problem with the argument is that it is not sound . In order for a deductive argument to be sound, the argument must be valid and all the premises must be true. Model theory analyzes formulae with respect to particular classes of interpretation in suitable mathematical structures. On this reading,

384-468: Is possible to discuss types of XML, as expressed within a Document Type Definition (DTD). Well-formed documents also bring into focus the issue of valid versus correct XML. According to the W3 Organization, valid documents are those that validate against a DTD. The rules of validity mean that a document complies with the restraints stated within a DTD. Thus, tags or entities must be in conformity to

408-564: Is serialized as XML. There are also serialization formats for Binary XML , CSV , and JSON . XML Information Set instances: This World Wide Web –related article is a stub . You can help Misplaced Pages by expanding it . Well-formed XML document A well-formed document in XML is a document that "adheres to the syntax rules specified by the XML 1.0 specification in that it must satisfy both physical and logical structures". At its base level well-formed documents require that: To be

432-431: Is that whether an argument is valid is a matter of the argument's logical form. Many techniques are employed by logicians to represent an argument's logical form. A simple example, applied to two of the above illustrations, is the following: Let the letters 'P', 'Q', and 'S' stand, respectively, for the set of men, the set of mortals, and Socrates. Using these symbols, the first argument may be abbreviated as: Similarly,

456-530: Is true under every possible interpretation of the language. In propositional logic, they are tautologies . A statement can be called valid, i.e. logical truth, in some systems of logic like in Modal logic if the statement is true in all interpretations. In Aristotelian logic statements are not valid per se. Validity refers to entire arguments. The same is true in propositional logic (statements can be true or false but not called valid or invalid). Validity of deduction

480-539: The argument is logically 'invalid', even though the conclusion could be considered 'true' in general terms. The premise 'All men are immortal' would likewise be deemed false outside of the framework of classical logic. However, within that system 'true' and 'false' essentially function more like mathematical states such as binary 1s and 0s than the philosophical concepts normally associated with those terms. Formal arguments that are invalid are often associated with at least one fallacy which should be verifiable. A standard view

504-400: The premises, instead it merely necessitates that conclusion follows from the premises without violating the correctness of the logical form . If also the premises of a valid argument are proven true, this is said to be sound . The corresponding conditional of a valid argument is a logical truth and the negation of its corresponding conditional is a contradiction . The conclusion is

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528-418: The rules and relations established within a DTD. However, there is no control on whether a tag or entity is correct. Thus a first level head tag could be applied to a second level head object and be valid, while incorrect. The emphasis on well-formed documents has developed within the publishing industry where the use of left and right angle bracket delimited information has become problematic. Emphasis on

552-416: The third argument becomes: An argument is termed formally valid if it has structural self-consistency, i.e. if when the operands between premises are all true, the derived conclusion is always also true. In the third example, the initial premises cannot logically result in the conclusion and is therefore categorized as an invalid argument. A formula of a formal language is a valid formula if and only if it

576-435: The well-formed document allows for the definition, delimiting, and nesting of content to be managed within programs that are not XML, per se, but exhibit the characteristics or potential for being well formed. There are several tools available to determine if a given XML document is well formed. Validity (logic) In logic , specifically in deductive reasoning , an argument is valid if and only if it takes

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