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Published

September 21

vr.tr.september-21 · thing-q2891

Let an agent handle September 21 as a calendar date with weekday computation, observances attributed to their traditions and sourced events.

Thing Registry Cross-cutting context XCT.TME
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

Date Calendar facts.

Weekday

Computation.

Weekday

Weekday.

  1. On which weekday does September 21 fall in this year? measurement
  2. Is it a leap year? boundary

Calendar

Julian or Gregorian.

Calendar

Calendar system.

  1. Is the Julian or Gregorian calendar meant? boundary
  2. What is the equivalent date in the other calendar? measurement
Observances Holidays.

Holiday

Public holiday.

Holiday

Holiday status.

  1. Is September 21 a public holiday or observance here? provenance
  2. Which tradition or law sets it? provenance

Attribution

Traditions.

Attribution

Attributed observances.

  1. Which countries or communities observe something on this date, according to them? provenance
  2. Is the observance attributed rather than assumed? boundary
History Past events.

Events

On this day.

Events

Historical events.

  1. Which notable events happened on September 21, according to reliable sources? provenance
  2. Are dates given in the same calendar? boundary

Anniversaries

Recurring.

Anniversaries

Anniversaries.

  1. Which anniversaries fall on this date this year? provenance
  2. Which are round numbers? measurement
Planning Scheduling.

Countdown

Days until.

Countdown

Countdown.

  1. How many days until the next September 21? measurement
  2. From which date? definition

Work

Working day.

Work

Working day.

  1. Is it a working day for this organisation? provenance
  2. Do deadlines move? boundary

Classifiers Filled

Family
Thing Registry
Category
Cross-cutting context
Entry kind
thing
Plane
XCT
Domain
XCT.TME

What it is Filled

September 21, day 264 (day 265 in leap years) of the year in the Gregorian calendar, with 101 days remaining in both common and leap years. September 21 is the International Day of Peace and World Alzheimer s Day, and Independence Day in Malta, marking 1964, in Belize, marking 1981, and in Armenia, marking the 1991 referendum.

Why it exists Filled

Let an agent handle September 21 as a calendar date with weekday computation, observances attributed to their traditions and sourced events.

Distinguishing features Filled

  • The twenty-first day of September
  • Weekday varies by year
  • Observances vary by place
  • Julian and Gregorian dates differ by 13 days in this era

What robots and AI may and may not do Filled

Must not

  • Present observances such as the International Day of Peace as holidays everywhere.
  • Present on-this-day events without sources.
  • Mix Julian and Gregorian dates when reporting historical events.

Only with a human decision

  • Scheduling public events or communications around a national day on someone's behalf.

May

  • Give the day's position in the Gregorian calendar and its recognized observances with their sources.
  • Note which countries observe independence days on this date.

Moral aspects Filled

  • National days of Malta, Belize and Armenia carry meaning for their people.
  • World Alzheimer's Day should be described with respect for those living with dementia.

Who is affected

  • People of the countries marking the day
  • People living with dementia

Owners Filled

Steward

Nobody: a calendar date held in common.

Links to other meta-models Filled

parent

  • Q11187254 - registry parent class

related

  • September - month
  • September 20 - date
  • calendar date - category
  • ISO 8601 - notation

What else AI and robots need to interact with it Filled

Identity and identifiers required Filled

  • Vercy registry: vr.tr.september-21
  • Wikidata: Q2891 (https://www.wikidata.org/wiki/Q2891)
  • ISO 8601: --09-21 recurring date

Direct properties not applicable Not applicable

  • day of year: 264 or 265 day - common year, leap year where different
  • days remaining: 101 days

Plane XCT: no invented physical properties.

Recognition optional Filled

  • Written 21 September or September 21
  • ISO format --09-21
  • Observances vary by country and tradition
  • A date on calendars.

Capabilities and actions required Filled

  • compute its weekday in a given year
  • check local and international observances
  • find sourced historical events
  • schedule events

Hazards and failure modes required Filled

  • Assuming observances are universal
  • Unsourced on-this-day events
  • Mixing Julian and Gregorian dates

Standards and interfaces required Filled

  • ISO 8601
  • National public holiday laws

Context of use required Filled

  • A calendar date for scheduling, holidays and anniversaries.
  • the recurring calendar date
  • specific dated days in given years

Sources Filled

  1. Wikidata item Q2891: September 21 - identity and sense of the item
  2. Wikipedia: September 21 - general description of the item

Open questions

  • Should dated days be separate entries?
  • How should observances be linked?
  • How should events be sourced?

Machine files

Card as JSON Specification Card backlog vercy.card/1

Provenance

thing registry research (pass 2) · unreviewed

Built from: models/things/publications/thing-q2891/spec.json