This chapter specifies purpose, functional requirements, and metadata for the Items that that a Process can act on in an M-Instance. Items are Data and Metadata supported and identified by an M-Instance. They are grouped in seven categories.

1  General 2  User 3  Interaction 4  Service Access
1.1     M-Instance 2.1     Account 3.1     Message 4.1     AuthenticateIn
1.2     M-Capabilities 2.2     Activity Data 3.2     P-Capabilities 4.2     AuthenticateOut
1.3     M-Environment 2.3     Personal Profile 3.3     Request-Action 4.3     DiscoverIn
1.4     Identifier 2.4     Social Graph 3.4     Response-Action 4.4     DiscoverOut
1.5     Rules 2.5     Personal Data 7  Space 4.5     InformIn
1.6     Rights 6   Perception 7.1     M-Location 4.6     InformOut
1.7     Program 6.1     Event 7.2     U-Location 4.7     InterpretIn
1.8     Contract 6.2     Experience 4.8     InterpretOut
5  Finance 6.3     Interaction    
5.1     Asset 6.4     Map.
5.2     Ledger 6.5     Model
5.3     Provenance. 6.6     Object
5.4     Transaction 6.7     Scene
5.5     Value 6.8     Stream    
5.6     Wallet 6.9     Summary

1       General Items

1      M-Instance

Purpose An implementation of MPAI-Metaverse Model – Architecture.
Functional Requirements 1.     An M-Instance implements a Functional Profile of MPAI Metaverse Model – Architecture.

2.     An M-Instance may

2.1.  Add Functionalities not supported by MPAI-Metaverse Model – Architecture. In this case full Interoperability with other M-Instances may not be achieved.

2.2.  Enables the creation of M-Environments.

Metadata
M-InstanceID The ID of the M-Instance.
DescrMdata Any description of the M-Instance.

1.2      M-Capabilities

Purpose An Item providing the list of features of an M-Instance.
Functional Requirements An M-Instance may show its M-Capabilities, including:

1.     Profile of the M-Instance.

2.     Data Formats supported by Items (needs a Taxonomy).

3.     Services supported (needs a Taxonomy).

Metadata
M-CapabilitiesID The ID of the M-Capabilities.
DescrMdata Any description of the M-Capabilities.

1.3      M-Environment

Purpose An Identified administrative subset of an M-Instance.
Functional Requirements An M-Environment may expose Rules concerning the definition, Identification, and access to M-Locations.
Metadata
M-EnvironmentID The ID of the M-Environment.
DescrMdata Any description of the M-Environment.

1.4      Identifier

Purpose  An Item that uniquely references an Item in an M-Instance.
Functional Requirements An Item can have more than one Identifier.

An Identifier of an Item may have a hierarchical structure in case it is useful to Identify an Item based on the M-Instance, the M-Environment:

1.     M-InstanceID

2.     M-EnvironmentID

3.     ItemID.

Metadata
DescrMdata Any description of the M-Environment.

1.5      Rules

Purpose An Item expressing the terms and conditions under which a human deploys a User in an M-Instance or M-Environment.
Functional Requirements The Rules

1.       Shall express the permissions, obligations, and prohibitions with respect to Actions performed by a User on Items.

2.       May grant a User the Rights to:

2.1.      Make Transactions.

2.2.      Export Items to another Metaverse.

3.       May grant a visitor (non-Registered human) limited Rights.

Metadata
RulesID The ID of the Rules.
M-InstanceID The ID of the M-Instance “where the Rules hold”.
DescrMdata Any descriptive Metadata.

1.6      Rights

Purpose An Item expressing the ability of a Process to perform Actions on an Item during Times, at M-Locations, and U-Locations.
Functional Requirements Rules may waive the need for certain Processes to hold certain Rights to perform certain Actions at certain Times.
Metadata
RightsID The ID of the Rights.
DescrMdata Any description of the Rights.

1.7      Program

Purpose An Item containing code that can be executed.
Functional Requirements The code:

1.     Shall be executable in the M-Instance.

2.     May be subject to certification before being admitted to the M-Instance.

Metadata
ProgramID The ID of the Program.
DescrMdata Any descriptive Metadata.

1.8      Contract

Purpose A Program stored on a Device that is activated by an external entity, e.g., a User, or another activated Contract.
Functional Requirements The Data of a Contract shall be in a form that allows execution in the M-Instance.

A Contract may be subject to a certification carried out by or on behalf of the M-Instance Manager before it can be imported into an M-Instance.

Metadata
ContractID The ID of the Contract.
DescrMdata Any description of the Contract.

2       Human and User-related Items

2.1      Account

Purpose An Item that uniquely references a human who has Registered.
Functional Requirements A User may have more than one Account in one or more M-Instances or M-Environments.

An Account shall include:

1.     The ID of the Registered human.

2.     An M-Instance-specific subset of the Registered human’s Personal Data.

3.     The Rights held by each User in the M-Instance/M-Environment.

4.     The IDs of Devices, Apps, and Users, and Personae.

Metadata
AccountID The ID of the Account.
humanID The ID of the Account holder.
M-InstanceID The ID of the M-Instance the Account refers to.
DescrMdata Any description of the Account.

2.2      Activity Data

Purpose An Item containing the record of all the Actions made by a User.
Functional Requirements Activity Data shall include:

1.     The M-Instance ID.

2.     The duration the Activity Data refer to.

3.     The list of Interactions.

Metadata
ActivityDataID The ID of the Activity Data.
UserID The ID of the User the Activity Data refers to.
M-InstanceID The ID of the M-Instance the Account refers to.
DescrMdata Any description of the Activity Data.

2.3      Personal Profile

Purpose An Item containing the Data about the human represented by a User.
Functional Requirements The Personal Profile may include:

1.     First Name

2.     Last Name

3.     Address

4.     Nationality.

5.     Age.

Metadata
PersonalProfileID The ID of the Personal Profile.
humanID The ID of the human the Personal Profile refers to.
DescrMdata Any description of the Personal Profile.

2.4      Social Graph

Purpose A representation of the network of connections with Items and Processes developed by a User.
Functional Requirements The Social Graph represents the Times and M-Locations of Interactions with Items and Processes.
Metadata
SocialGraphID The ID of the Social Graph.
UserID The ID of the User the Social Graph refers to.
DescrMdata Any description of the Social Graph.

2.5      Personal Data

Purpose An Item containing Activity Data, Personae, and Social Graph of a User.
Functional Requirements Personal Data includes the following Data:

1.     Rights and Obligations of the Account-holding human.

2.     The Personal Profile of the human.

3.     The Personae that the Users of the human may assume.

4.     The Activity Data of the Users of the human.

5.     The Social Graphs of the Users of the human.

Metadata
PersonalDataID ID of PersonalData.
AccountID ID of Account held by User.
PersonalProfileID ID of Personal Profile.
PersonaIDs IDs of Personae held User.
ActivityDataIDs ID of Activity Data
SocialGraphIDs ID of SocialGraph
DescrMdata Any description of the Personal Data.

3       Items for Process Interaction

3.1      Message

Purpose An Item a Source Process MM-Sends to a Destination Process.
Functional Requirements A Message may contain:

1.     An Item, or

2.     Data and Metadata

Metadata
MessageID The ID of the Message.
DescrMetadata Any description of the Message.

3.2      P-Capabilities

Purpose An Items containing a description of the characteristics of a Process.
Functional Requirements 1.       Provision of the P-Capabilities Item by a Process is optional.

2.       The characteristics of all Processes are:

2.1.      List of Actions that can be performed.

2.2.      List of Items supported with Data Formats.

2.3.      List of Data Types supported.

2.4.      The cost of performing an Action.

3.       Additionally, a Device has: Apps on board.

4.       Additionally, a User has: Human represented by User.

Metadata
PCapabilitiesID The ID of P-Capabilities of a Process.
Descriptive Metadata Any description of the P-Capabilities.

3.3      Request-Action

Purpose An Item containing the request to a Process to perform an Action as defined in MPAI-MMM – Architecture.
Functional Requirements A Request-Action shall include:

1.     Time the Request-Action was issued.

2.     The Source ProcessID.

3.     The Destination ProcessID.

4.     The Action requested.

5.     The ItemIDs relevant to the Action.

6.     The Locations of the Items.

7.     The Locations of the output Items produced by the Request-Action.

8.     The requested Rights on the output Items.

Metadata
Request-ActionID The ID of the Request-Action.
DescrMdata Any descriptive Metadata.

3.4      Response-Action

Purpose An Item containing the response of a Process to a Request-Action as defined in MPAI-MMM – Architecture.
Functional Requirements The Response-Item shall include:

1.     Time the Response-Action was issued.

2.     The Source ProcessID (Source refers to the Process that issued the request).

3.     The Destination ProcessID.

4.     The output Items produced by the Request-Action.

5.     Error messages.

Metadata
Request-ActionID The ID of the Response-Action.
DescrMdata Any descriptive Metadata.

4       Items for Service Access

4.1      AuthenticateIn

Purpose An Item containing:

1.     The Entity or the ID of the Entity to be Authenticated.

2.     Information related to the rendering of AuthenticateOut (optional).

Functional Requirements Examples of Entity that may be subject to Authentication can be:

1.     Speech produced by a User.

2.     The visual appearance of a User.

3.     …

Information on the rendering of InterpretOut may be provided by:

1.     Media type (text, speech, image, etc.) used for rendering.

2.     Spatial Attitude of the Object rendering AuthenticateOut.

Metadata
AuthenticateInID The ID of the AuthenticateIn Item.
UserID The ID of the User generating the AuthenticateIn Item.
ServiceID The ID of the Service providing Authentication Services.
RightsID The ID of the Rights “to Act on the AuthenticateIn Item” granted to the Authentication Service.
DescrMdata Any description of the AuthenticateIn Item.

4.2      AuthenticateOut

Purpose An Item containing the result of the Service Acting on the Request-Authenticate Item and information about its rendering.
Functional Requirements AuthenticateOut shall be:

1.     Made available to the User as Item, and

1.     Rendered to the User as a perceptible Object as specified in AuthenticateIn.

Metadata
AuthenticateOutID The ID of the Request-Authenticate Item.
ServiceID The ID of the Service providing the AuthenticateOut Item.
UserID The ID of the User having requested the AuthenticateOut Item.
RightsID The ID of the Rights “to Act on the AuthenticateOut Item” granted to UserID.
Descr­Mdata Any description of the AuthenticateOut Item.

4.3      DiscoverIn

Purpose An Item containing:

1.     A description of the Items to be Discovered or recommended.

2.     Information related to the rendering of DiscoverOut.

Functional Requirements Items candidate for Discovery may be described by:

1.     Verbal/text description

2.     Similar Items

3.     Belonging to specific M-Instances/M-Environments/M-Locations

4.     Belonging to specific sections of Activity Data.

Information on DiscoverOut Rendering may be provided by:

1.     Media type used for rendering.

2.     Spatial Attitude of the Object rendering DiscoverOut.

Metadata
DiscoverInID The ID of the DiscoverIn Item.
UserID The ID of the User generating the DiscoverIn Item.
ServiceID The ID of the Service providing Discovery Services.
RightsID The ID of the Rights “to Act on the DiscoverIn Item” granted to the Discovery Service.
DescrMdata Any description of the DiscoverIn Item.

4.4      DiscoverOut

Purpose An Item containing the description of the Items Discovered and information related to its rendering.
Functional Requirements Discovered Items

1.     Shall be Identified by their IDs.

2.     May be:

2.1.  Accompanied by descriptions.

2.2.  Rendered to the User as a perceptible Object.

Metadata
DiscoverOutID The ID of the Request-Discover Item.
ServiceID The ID of the Service providing the DiscoverOut Item.
UserID The ID of the User having requested the DiscoverOut Item.
RightsID The ID of the Rights “to Act on the DiscoverOut Item” granted to UserID.
DescrMdata Any description of the DiscoverOut Item.

4.5      InformIn

Purpose An Item containing:

1.     A description of the Item about which information is requested.

2.     Information related to the rendering of InformOut.

Functional Requirements InformIn may refer to:

1.     Item Metadata

2.     Any other information that a Service may provide on the Item.

Information on the rendering of InformOut may be provided by:

1.     Media types used for rendering.

2.     Spatial Attitude of InformOut rendered Object.

Metadata
InformInID The ID of the InformIn Item.
UserID The ID of the User generating the InformIn Item.
ServiceID The ID of the Service providing Inform Services.
RightsID The ID of the Rights “to Act on the InformIn Item” granted to the Inform Service.
DescrMdata Any description of the InformIn Item.

4.6      InformOut

Purpose  An Item containing the description of the Item object of an InformIn.
Functional Requirements InformOut shall be:

1.     Made available to the User as an Item, or

2.     Rendered to the User as a perceptible Object.

Metadata
InformOutID The ID of the InformOut Item.
ServiceID The ID of the Service providing the InformOut Item.
UserID The ID of the User having requested the InformIn Item.
RightsID The ID of the Rights “to Act on the InformOut Item” granted to UserID.
DescrMdata Any description of the InformOut Item.

4.7      InterpretIn

Purpose An Item containing:

1.     The ID or the Item to be Interpreted.

2.     Information related to the rendering of InterpretOut.

Functional Requirements Items candidate for interpretation may be provided as the Item or Identified by ItemID.

Information on InterpretOut Rendering may be provided by:

1.     Media type used for rendering.

2.     Spatial Attitude of InterpretOut rendered Object.

Metadata
DiscoverInID The ID of the InterpretIn Item.
UserID The ID of the User generating the InterpretIn Item.
ServiceID The ID of the Service providing Interpret Services.
RightsID The ID of the Rights “to Act on the InterpretIn Item” granted to the Interpret Service.
DescrMdata Any description of the InterpretIn Item.

4.8      InterpretOut

Purpose An Item containing the description of the Item provided in response to an InterpretIn Item.
Functional Requirements Interpreted Items shall be:

1.     Described by the IDs of the Interpreted Item.

2.     Rendered to the User as a perceptible Object.

Metadata
InterpretOutID The ID of the InterpretOut Item.
ServiceID The ID of the Service providing the InterpretOut Item.
UserID The ID of the User having requested the InterpretOut Item.
RightsID The ID of the Rights “to Act on the InterpretOut Item” granted to UserID.
DescrMdata Any description of the InterpretOut Item.

5       Finance-related Items

1.5.1      Asset

Purpose An Item that can be Transacted.
Functional Requirements An Asset

1.     May be:

1.1.  MM-Embedded at an M-Location.

1.2.  Posted to a Service (e.g., a marketplace).

2.     Shall:

2.1.  Preserve the Data Formats of the Item that has spawned it.

2.2.  Include the date it was Modified as Asset.

Metadata
AssetID The ID of the Asset.
UserIDs The ID of the Users “having Rights to the Asset”.
ProvenanceID The ID of the Provenance of the Asset.
DescrMdata Any description of the Asset.

5.2      Ledger

Purpose An Item containing a list of Transactions involving Assets.
Functional Requirements The list of entries of a Ledger may be based on:

1.     The types of Items included in the Ledger.

2.     The Items at an M-Location.

3.     The Users to which a Ledger refers.

4.     The duration in time to which a Ledger refers.

5.     The Items in a DiscoverOut Item.

Metadata
LedgerID The ID of the Ledger.
UserID The ID of the User who “has produced the Ledger”.
DescrMdata Any descriptive Metadata.

1.5.3      Provenance

Purpose The Ledger associated and included in the metadata of a specific Asset.
Functional Requirements The Provenance Item shall include the list of all Transactions executed:

1.     On an Asset.

2.     Starting from the first Transaction and including the last.

3.     The Marketplace on which a Transaction may have been performed.

Metadata
ProvenanceID The ID of the Provenance.
DescrMdata Any descriptive Metadata.

5.4      Transaction

Purpose Item representing the changed state of the Wallets and the Rights of a seller User and a buyer User on an Asset and optionally of the Service facilitating/enabling the Transaction
Functional Requirements The Transaction shall represent:

1.     The Time the Transaction is performed.

2.     The Value moving into the Wallet of User 1 (seller).

3.     The Value moved from the Wallet of User2 (buyer).

4.     The Value moved into the Wallet of User 3 (service) – optional.

5.     The Time the Value has moved to the seller Wallet.

6.     The Time the Value has moved from the buyer Wallet.

7.     The Rights to Act on the Asset owned by User1 after Time.

8.     The Rights to Act on the Asset owned by User2 after Time.

Metadata
TransactionID The ID of the Transaction.
AssetID The ID of the Asset the Transaction refers to.
UserID The ID of User1 “who grants the Rights”.
RightsID The ID of the Rights held by User1 after Time.
WalletID The ID of the Wallet of User1.
TargetUserID The ID of the User2 “who is granted the Rights”.
OutRightsID The ID of the Rights “granted to User2”.
TargetWalletID The ID of the Wallet of User2.
ServiceID The ID of the Marketplace.
ServiceWalletID The ID of the Wallet of the Marketplace.
DescrMdata Any description of the Transaction.

5.5      Value

Purpose An Amount and the Currency with which the Amount is expressed.
Functional Requirements Value shall have a representation that enables the expression of the Amount and the Currency used to represent the Amount.
Metadata
ValueID The ID of the Value.
DescrMdata Any description of the User.

5.6      Wallet

Purpose A container of Values.
Functional Requirements A Wallet shall enable the representation of the Amounts in each Currency.
Metadata
WalletID The ID of the Wallet.
UserID The ID of the User “having Rights to the Wallet”.
RightsID The ID of the Rights “User has on the Wallet”.
DescrMdata Any description of the User.

6       Perception-related Items

6.1      Event

Purpose An Entity that includes selected Entities at an M-Location during a period.
Functional Requirements An Event shall include:

1.     Start Time and End Time.

2.     M-LocationID.

3.     List of selected Entities of the M-Location.

Metadata
EventID The ID of the Event.
AuthorID The ID of the User “who authored the Event”.
ParentItemID The ID of the Entity “from which the Event is derived”.
DescrMdata Any description of the Event.

6.2      Experience

Purpose An Entity comprising User-selected Entities of an Event and the User Interactions with the selected Entities.
Functional Requirements An Experience shall include:

1.     ID of User the Experience refers to.

2.     EventID

3.     Start Time and End Time of the Experience.

4.     List of Entities perceived and Interactions made by a User.

Metadata
ExperienceID The ID of the Experience.
AuthorID The ID of the User “who authored the Experience”.
ParentEntityID The ID of the Event spawning the Experience.
DescrMdata Any description of the Experience.

6.3      Interaction

Purpose An Item containing the Actions performed by a User on an Entity.
Functional Requirements An Interaction includes:

1.     The Request-Action issued by a User on an Entity at an M-Location and the corresponding Time.

2.     The Response-Action issued by the requested Process.

Metadata
InteractionID The ID of the Interaction.
UserID The ID of the User “who created the Interaction”.
EntityID The ID of Entity “the User Interacted with”.
DescrMdata Any description of the Interaction.

6.4      Map

Purpose An Item providing U-Locations and corresponding M-Locations and/or Entities.
Functional Requirements A Map shall include a list composed of:

1.     U-LocationID and Metadata related to the U-LocationID.

2.     M-LocationID(s) and/or EntityIDs, and Metadata related to the M-LocationID(s) and/or EntityIDs corresponding to the U-LocationID.

Metadata
MapID The ID of the Map.
AuthorID The ID of the User “who authored the Map”.
Auth.ToolID The ID of the Service “who provided the Authoring tool”.

6.5      Model

Purpose An Object having features allowing it to be MM-Animated or UM-Animated.
Functional Requirements A Model shall include:

1.     The type(s) of Media (Audio-Visual-Haptic) composing the Model.

2.     The type(s) of Animation the Model can accept.

Metadata
ModelID The ID of the Object Model.
AuthorID The ID of the User “who authored or imported the DataMdata used to make the Object Model”.
Auth.ToolID The ID of the Service “who provided the Authoring tool”.
DescrMdata Any description of the Model.

6.6      Object

Purpose An Item with perceptibility attributes that include one of the following Media types: Audio, Visual, and Haptics.
Functional Requirements An Object shall include:

1.     The type(s) of Media (Audio-Visual-Haptic) composing the Model.

2.     The Data representation

2.1.  Audio Data representation, e.g.:

2.1.1.     Mono (e.g., speech)

2.1.2.     Stereo

2.1.3.     Multichannel

2.1.4.     Microphone array

2.1.5.     Spatial Audio

2.2.  Visual Data representation, e.g.:

2.2.1.     Still

2.2.2.     Mono

2.2.3.     Camera array

2.2.4.     Light field

2.2.5.     Holography

2.2.6.     RADAR

2.2.7.     LiDAR

2.3.  Haptic Data representation.

3.     The type of Object, e.g.:

3.1.  An inanimate Object (e.g., a table).

3.2.  A Model (e.g., a Persona).

3.3.  An autonomous Object (e.g., a robot).

3.4.  An animal, possibly with high accuracy.

3.5.  A human, possibly with high accuracy.

4.     The Data Format used.

Metadata
Object ID The ID of the Object Identified by ObjectID.
AuthorID The ID of the User “who authored the Object or imported the DataMdata used to make the Object”.
Auth.­ToolID The ID of the Service “who provided the Authoring tool”
DescrMdata Any description of the Object.

6.7      Scene

Purpose A possibly hierarchical Composition of Objects having Spatial Attitudes.
Functional Requirements 1.     It should be possible to MM-Embed a Scene at a specified M-Location.

2.     The Scene may be MM-/UM-Animated.

3.     The Objects in the Scene may be MM-/UM-Animated.

Metadata
SceneID The ID of the Scene Identified by SceneID
AuthorID The ID of the User “who authored the Scene”.
Auth.ToolID The ID of the Service “who provided the Creation tool”.
DescrMdata Any description of the Scene.

6.8      Stream

Purpose An Item made of a continuous flow of Data, e.g., an Animation Stream.
Functional Requirements Streams may be used to:

1.     UM-Animate a Model.

2.     UM-Animate an Object.

3.     UM-Animate a Scene.

4.     Represent a Digitised Object (e.g., a Point Cloud) MM-Embedded at an M-Location.

Metadata
StreamID The ID of the Stream.
AuthorID The ID of the User “who created or imported the Stream”.
Auth.ToolID The ID of the Service “who provided the Creation tool”.
DescrMdata Any description of the Stream.

6.9      Summary

Purpose An abridged outline of the content of the utterance(s) of one or more Users possibly including their Personal Statuses.
Functional Requirements A Summary contains Text and Personal Status labels.
Metadata
SummaryID The ID of the Summary Item.
UserID The ID of the User “who authored the Summary”.
DescrMdata Any description of the Summary.

7       Space-related Items

7.1      M-Location

Purpose A delimited space of an M-Instance.
Functional Requirements An M-Location:

1.     Shall define the space of the M-Instance or M-Environment that is included in the M-Location.

2.     May enable the creation of sub-spaces defining sub-M-Locations included in the M-Location (e.g., the rooms of an apartment).

Metadata
M-LocationID The ID of the M-Location Item.
DescrMdata Any description of the M-Location.

7.2      U-Location

Purpose A delimited portion of the Universe.
Functional Requirements A U-Location:

1.     Shall define the space in the Universe that is included in the U-Location.

2.     May enable the definition of sub-spaces defining sub-U-Locations included in the U-Location.

The enforcement of Rights to a U-Location is not part of MPAI-MMM – Architecture.

Metadata
U-LocationID The ID of the U-Location.
DescrMdata Any description of the U-Location.