We can consider a resource to be one of many members of a very broad category, as the unique instance of a category with only one member, or anywhere in between.

(See §4.1.1, “What Is a Resource?”)

The size of the category—the number of resources that are treated as equivalent—is determined by the properties or characteristics we consider when we examine the resource.

(See §4.1.1, “What Is a Resource?”)

Organizing systems for physical information resources emphasize description resources or surrogates like bibliographic records that describe the information content rather than their physical properties.

(See §4.1.1.2, “Bibliographic Resources, Information Components, and “Smart Things” as Resources”)

An identifier is a special kind of name assigned in a controlled manner and governed by rules that define possible values and naming conventions. The design of a scheme for persistent identifiers must consider both the required time frame and the number of resources to be identified.

(See §4.1.2, “Identity, Identifiers, and Names”)

Active resources create effects or value on their own, sometimes when they initiate interactions with passive resources. Active resources can be people, other living resources, computational agents, active information sources, web-based services, self-driving cars, robots, appliances, machines or otherwise ordinary objects like light bulbs, umbrellas, and shoes that have been made “smarter.”

(See §4.2.3.2, “Active or Operant Resources”)

More fine-grained organization reduces recall, the number of resources you find or retrieve in response to a query, but increases the precision of the recalled set, the proportion of recalled items that are relevant.

(See §4.3.3, “Identity and Information Components”)

Agency is the extent to which a resource can initiate actions on its own. We can define a continuum between completely passive resources that cannot initiate any actions and active resources that can initiate actions based on information they sense from their environments or obtain through interactions with other resources.

(See §4.2.3, “Resource Agency”)

Resources become active resources when they contain sensing and communication capabilities.

(See §4.2.3, “Resource Agency”)

Which resources are primary and which are metadata is often just a decision about which resource is the focus of our attention.

(See §4.2.4, “Resource Focus”)

It can be useful to view domains of information resources on the Document Type Spectrum from weakly-structured narrative content to highly structured transactional content.

(See the sidebar, The Document Type Spectrum)

The concept of identity for bibliographic resources has evolved into a four-level abstraction hierarchy between the abstract work, an expression in multiple formats or genres, a particular manifestation in one of those formats or genres, and a specific physical item.

(See §4.3.2, “Identity and Bibliographic Resources” and Figure 4.5, “The FRBR Abstraction Hierarchy.”)

If the resource has an IP address, it is part of the “Internet of Things.”

(See §4.3.4, “Identity and Active Resources”.)

Every natural language offers more than one way to express any thought, and in particular there are usually many words that can be used to refer to the same thing or concept.

(See §4.4.2, “The Problems of Naming”)

Many resources are given names based on attributes that can be problematic later if the attribute changes in value or interpretation.

(See §4.4.2.4, “Names that Assume Impermanent Attributes”)

The semantic gap is the difference in perspective in naming and description when resources are described by automated processes rather than by people.

(See §4.4.2.5, “The Semantic Gap”)

The most basic principle of naming is to choose names that are informative.

(See §4.4.3.1, “Make Names Informative”)

One way to encourage good names for a given resource domain or task is to establish a controlled vocabulary. A controlled vocabulary is like a fixed or closed dictionary that includes the terms that can be used in a particular domain. A controlled vocabulary shrinks the number of words used, reducing synonymy and homonymy, eliminating undesirable associations, leaving behind a set of words with precisely defined meanings and rules governing their use.

(See §4.4.3.2, “Use Controlled Vocabularies”)

For bibliographic resources important aspects of vocabulary control include determining the authoritative forms for author names, uniform titles of works, and the set of terms by which a particular subject will be known. In library science, the process of creating and maintaining these standard names and terms is known as authority control.

(See §4.4.3.2, “Use Controlled Vocabularies”)

Preservation and governance are activities carried out to ensure that resources will last as long as they are needed.

(See §4.5.1, “Persistence”)

Many resources, or their properties, also have locative or temporal effectivity, meaning that they come into effect at a particular time and/or place; will almost certainly cease to be effective at some future date, and may cease to be effective in different places.

(See §4.5.2, “Effectivity”)

The only guarantee of a resource’s authenticity is having total oversight over the “chain of custody” from its creation to the present.

(See §4.5.3, “Authenticity” and §4.5.4, “Provenance”)