← Back to catalogue
Published

calendar system

vr.tr.calendar-system · thing-q12132

Let an agent handle calendar systems by type, epoch, rules, conversion and use.

Thing Registry Information and virtual systems INF.KNW
Bundle → Layer → Finding → QuestionsClassifiersWhat it isWhy it existsDistinguishing featuresWhat robots and AI may and may not doMoral aspectsOwnersLinks to other meta-modelsIdentity and identifiersDirect propertiesRecognitionCapabilities and actionsHazards and failure modesStandards and interfacesContext of useSources

Bundle → Layer → Finding → Questions Filled

4 bundles · 8 layers · 8 findings · 16 questions

System Which calendar.

Type

Solar, lunar.

Type

Calendar type.

  1. Which calendar is used, and what kind is it? definition
  2. What is its epoch? provenance

Rules

Months and leaps.

Rules

Rules.

  1. How are months and leap periods determined? definition
  2. Are months fixed or based on sightings? boundary
Conversion Between calendars.

Convert

Algorithm.

Convert

Conversion.

  1. What is this date in another calendar? measurement
  2. Which algorithm or authority? provenance

Historical

Old dates.

Historical

Historical dates.

  1. Was the date recorded in the Julian or another calendar? boundary
  2. When did the region switch? provenance
Observances Holidays.

Holidays

Dates.

Holidays

Holiday dates.

  1. When does this holiday fall this year? measurement
  2. According to which authority? provenance

Variation

Local differences.

Variation

Local variation.

  1. Does the date vary by region or community? boundary
  2. Why? definition
Software Implementation.

Libraries

Support.

Libraries

Library support.

  1. Which libraries support this calendar? provenance
  2. Is CLDR data used? provenance

Display

Localisation.

Display

Localisation.

  1. How should dates be displayed for this locale? action
  2. Is the calendar shown explicitly? boundary

Classifiers Filled

Family
Thing Registry
Category
Information and virtual systems
Entry kind
thing
Plane
INF
Domain
INF.KNW
Other names and narrower kinds
Lukashian calendar, winter count, consularia, Schreibkalender, traditional calendar in Vietnam, Julian calendar, religious calendar, biodynamic calendar, old calendar, Directorium, Discordian calendar, fasti

What it is Filled

A system for organising days into periods such as weeks, months and years for social, religious, commercial or administrative purposes, using solar, lunar or lunisolar cycles, other cycles or purely arithmetic schemes, with examples including the Gregorian, Julian, Islamic, Hebrew, Chinese and traditional calendars.

Why it exists Filled

Let an agent handle calendar systems by type, epoch, rules, conversion and use.

Distinguishing features Filled

  • Organises days into cycles
  • Solar, lunar or lunisolar
  • Has an epoch and leap rules
  • Many in parallel use

What robots and AI may and may not do Filled

Must not

  • Present a converted historical date as certain when the source calendar is ambiguous.
  • Fix the date of a religious observance that depends on an authority's sighting or decision.
  • Treat one calendar as the only correct one or dismiss others as primitive.
  • Silently shift dates in records when changing calendar systems.

Only with a human decision

  • Declaring dates of religious festivals for a community.
  • Correcting dates in legal or historical records.

May

  • Convert dates between calendars, stating the rules and any uncertainty.
  • Show religious and civil dates side by side for planning.

Moral aspects Filled

  • Calendars carry religious and cultural identity, not just arithmetic.
  • Date errors can affect contracts, deadlines and observances.

Who is affected

  • Communities who keep the calendar
  • Historians and record users
  • People bound by dated obligations

Owners Filled

Steward

Nobody owns a calendar system; religious and civil authorities keep their own rules.

Links to other meta-models Filled

parent

  • Q130788 - registry parent class
  • Q3622126 - registry parent class

related

  • chronology and conceptual system - category
  • leap year and month - units
  • ISO 8601 - standard
  • holiday computation - application

What else AI and robots need to interact with it Filled

Identity and identifiers required Filled

  • Vercy registry: vr.tr.calendar-system
  • Wikidata: Q12132 (https://www.wikidata.org/wiki/Q12132)

Direct properties not applicable Not applicable

Not applicable

Plane INF: no invented physical properties.

Recognition optional Filled

  • Calendar names and eras
  • Month names and lengths
  • Record-keeping forms such as winter counts
  • Tables, almanacs and date notations.

Capabilities and actions required Filled

  • convert dates between calendars
  • compute holidays
  • understand leap rules
  • read historical dates correctly

Hazards and failure modes required Filled

  • Conversion errors
  • Confusing Julian and Gregorian dates
  • Lunar calendars depending on sighting

Standards and interfaces required Filled

  • ISO 8601 (Gregorian)
  • Unicode CLDR calendar data
  • National laws on official calendars

Context of use required Filled

  • Scheduling, recording dates and religious and civil observances.
  • solar calendars such as Gregorian
  • lunar calendars such as Islamic
  • lunisolar calendars such as Hebrew and Chinese
  • historical calendars such as Julian
  • traditional record systems such as winter counts

Sources Filled

  1. Wikidata item Q12132: calendar system - identity and sense of the item
  2. Wikipedia: Calendar - general description of the item

Open questions

  • Should each calendar be a separate entry?
  • How should conversion algorithms be linked?
  • How should sighting-based months be handled?

Machine files

Card as JSON Specification Card backlog vercy.card/1

Provenance

thing registry research (pass 2) · unreviewed

Built from: models/things/publications/thing-q12132/spec.json