In a formal system of logic used for knowledge representation, the open-world assumption is the assumption that the truth value of a statement may be true irrespective of whether or not it is known to be true. It is the opposite of the closed-world assumption, which holds that any statement that is true is also known to be true.ExampleThe language of logic programs with strong negation allows us to postulate the closed-world assumption for some predicates and leave the other predicates in the realm of the open-world assumption.

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dbo:abstract
  • En logique formelle, l’hypothèse du monde ouvert est la supposition selon laquelle la véracité d'une affirmation ne dépend pas de la connaissance d'un agent ou d'un observateur. Elle s'oppose à l'hypothèse du monde clos, dans laquelle l'absence d'information sur une affirmation est interprétée comme la preuve de sa fausseté. L'hypothèse du monde ouvert est notamment faite au sein des logiques descriptives. (fr)
  • In a formal system of logic used for knowledge representation, the open-world assumption is the assumption that the truth value of a statement may be true irrespective of whether or not it is known to be true. It is the opposite of the closed-world assumption, which holds that any statement that is true is also known to be true. The open-world assumption (OWA) codifies the informal notion that in general no single agent or observer has complete knowledge, and therefore cannot make the closed-world assumption. The OWA limits the kinds of inference and deductions an agent can make to those that follow from statements that are known to the agent to be true. In contrast, the closed world assumption allows an agent to infer, from its lack of knowledge of a statement being true, anything that follows from that statement being false. Heuristically, the open-world assumption applies when we represent knowledge within a system as we discover it, and where we cannot guarantee that we have discovered or will discover complete information. In the OWA, statements about knowledge that are not included in or inferred from the knowledge explicitly recorded in the system may be considered unknown, rather than wrong or false. Semantic Web languages such as OWL make the open-world assumption. The absence of a particular statement within the web means, in principle, that the statement has not been made explicitly yet, irrespective of whether it would be true or not, and irrespective of whether we believe that it would be true or not. In essence, from the absence of a statement alone, a deductive reasoner cannot (and must not) infer that the statement is false. Many procedural programming languages and databases make the closed-world assumption. For example, if a typical airline database does not contain a seat assignment for a traveler, it is assumed that the traveler has not checked in. The closed-world assumption typically applies when a system has complete control over information; this is the case with many database applications where the database transaction system acts as a central broker and arbiter of concurrent requests by multiple independent clients (e.g., airline booking agents). There are, however, many databases with incomplete information: for example, one cannot assume that because there is no mention on a patient's history of a particular allergy, that the patient does not suffer from that allergy. Example Under OWA, failure to derive a fact does not imply the opposite. For example, assume we only know that Mary is a citizen of France. From this information we can neither conclude that Paul is not a citizen of France, nor that he is. Therefore, we admit the fact that our knowledge of the world is incomplete. The open-world assumption is closely related to the monotonic nature of first-order logic: adding new information never falsifies a previous conclusion. Namely, if we subsequently learn that Paul is also a citizen of France, this does not change any earlier positive or negative conclusions. The language of logic programs with strong negation allows us to postulate the closed-world assumption for some predicates and leave the other predicates in the realm of the open-world assumption. (en)
  • 开放世界假定是当前没有陈述的事情是未知的假定。开放世界假定可以被认为暗含在 RDF 和 OWL 中,因为没有明确的包含在语义 web 或本体(ontology)中的所有元组,都被暗含的假定为是未知的事实而不是假的。例子 1. 陈述: "Mary"是"法国"的"公民"。 提问: Mary 是加拿大公民吗? "封闭世界"(比如 SQL 或 XML)回答: 否。 "开放世界"回答: 不知道(Mary 可能有双重国籍)。例子 2. 陈述: "Jane"的"母亲是""Mary"。 "母亲是"的"基数"为 1。 新陈述: "Jane"的"母亲是""Elizabeth"。 "封闭世界"反应: 错误。人只能有一个母亲。 "开放世界"反应: 新事实。"Mary""就是""Elizabeth"。 (zh)
  • Предположение об открытости мира, (ПОМ) — предположение в формальной логике о том, что истинность утверждения не зависит от того, «известно» ли какому-либо наблюдателю или агенту о верности данного утверждения.Оно противоположно предположению о замкнутости мира, из которого следует, что ложно любое утверждение, о котором не известно, что оно верно. (ru)
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rdfs:comment
  • 开放世界假定是当前没有陈述的事情是未知的假定。开放世界假定可以被认为暗含在 RDF 和 OWL 中,因为没有明确的包含在语义 web 或本体(ontology)中的所有元组,都被暗含的假定为是未知的事实而不是假的。例子 1. 陈述: "Mary"是"法国"的"公民"。 提问: Mary 是加拿大公民吗? "封闭世界"(比如 SQL 或 XML)回答: 否。 "开放世界"回答: 不知道(Mary 可能有双重国籍)。例子 2. 陈述: "Jane"的"母亲是""Mary"。 "母亲是"的"基数"为 1。 新陈述: "Jane"的"母亲是""Elizabeth"。 "封闭世界"反应: 错误。人只能有一个母亲。 "开放世界"反应: 新事实。"Mary""就是""Elizabeth"。 (zh)
  • Предположение об открытости мира, (ПОМ) — предположение в формальной логике о том, что истинность утверждения не зависит от того, «известно» ли какому-либо наблюдателю или агенту о верности данного утверждения.Оно противоположно предположению о замкнутости мира, из которого следует, что ложно любое утверждение, о котором не известно, что оно верно. (ru)
  • In a formal system of logic used for knowledge representation, the open-world assumption is the assumption that the truth value of a statement may be true irrespective of whether or not it is known to be true. It is the opposite of the closed-world assumption, which holds that any statement that is true is also known to be true.ExampleThe language of logic programs with strong negation allows us to postulate the closed-world assumption for some predicates and leave the other predicates in the realm of the open-world assumption. (en)
  • En logique formelle, l’hypothèse du monde ouvert est la supposition selon laquelle la véracité d'une affirmation ne dépend pas de la connaissance d'un agent ou d'un observateur. Elle s'oppose à l'hypothèse du monde clos, dans laquelle l'absence d'information sur une affirmation est interprétée comme la preuve de sa fausseté.L'hypothèse du monde ouvert est notamment faite au sein des logiques descriptives. (fr)
rdfs:label
  • Open-world assumption (en)
  • Hypothèse du monde ouvert (fr)
  • 开放世界假定 (zh)
  • Предположение об открытости мира (ru)
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