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Research draft

time

vr.tr.time · XCT.TME

Let an agent handle time as instants, durations and intervals with units, time scales and zones, and avoid the classic errors of mixing them.

Thing Registry Cross-cutting context

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify

Researched by: Claude

Purpose and description

Let an agent handle time as instants, durations and intervals with units, time scales and zones, and avoid the classic errors of mixing them.

The continuing progression of events from past through present to future, measured in seconds and larger units, and used to order events and measure durations.

What it is for: Ordering events, measuring durations, coordinating activity and scheduling.

It can be measure it, with clocks referenced to atomic time; record instants, with timestamps and time zones; compute durations and intervals; schedule and coordinate, across zones.

Distinguishing features

Instant, duration and interval are different things

Time scales differ: TAI, UTC, GPS time, local time

Local time depends on zone and daylight saving

Domain-specific times such as half-lives are durations

What it looks like

Not visible; shown by clocks, calendars and timestamps.

Physical character

SI base unit: second s - defined by the caesium-133 hyperfine transition

leap seconds inserted since 1972: 27 seconds - as of 2026

How it is recognised

Timestamps such as 2026-09-11T07:52:54Z

Durations such as PT3H or half-lives

Clock faces and displays

Related models

is divided into - calendar units

day, week, year

is measured by - instruments

clock

orders - events occur in time

event

is confused with - a date is a whole day, not an instant

calendar date

In practice

Families and kinds

instants and timestamps

durations and intervals

time scales: UTC, TAI, GPS

domain times: half-life, crystallisation time, paid time off

Identifiers

ISO 8601 timestamp YYYY-MM-DDThh:mm:ssZ standard representation

IANA time zone Region/City time zone database

Standards and regulation

SI definition of the second

ITU-R TF.460 on UTC

ISO 8601 and RFC 3339

National time zone law

Failure modes and hazards

Time zone and daylight saving errors

Clock drift and unsynchronised systems

Leap second handling bugs

Mixing local and UTC timestamps

Also called

paid time offreal-timeMoscosocrystallization timebiological half-lifeDöpplasma half-lifeTrading daylategraduation timelocal timeRancataXiaomi WatchGPS timepower reservecompletion timeconsultation hoursresidence timeregular trading hoursreckoning of timelaytimemilitary designation of days and hourstime by areaLyapunov timeextra timeretention timescreen timenarrative timeaeonair-timetime of arrivalproduct lifetimepropagation timedead timesymmetry minutebroadcasting timeSpace timesystem timetimestreamwall-clock time

+2

Where this came from

wikidata · CC0 1.0

Source repository Registry entry point

Also registered as vr.tr.time-event

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.

Kind of time value Instant, duration or interval.

Most time errors come from confusing kinds.

Instant

A point in time.

Instant

The instant and its zone.

  1. Is this an instant, and in which time zone or scale? definition
  2. How precise is it? measurement

Duration

A length of time.

Duration

The duration and unit.

  1. What duration is meant, in which unit? measurement
  2. Does it cross a daylight saving change? boundary
Scales and zones Which clock.

Time scales and zones must be named.

Time scale

UTC, TAI, GPS.

Time scale

The scale used.

  1. Which time scale is used? definition
  2. How are leap seconds handled? boundary

Time zone

Local time.

Zone

The zone and rules.

  1. Which IANA time zone applies? definition
  2. Have the zone rules changed recently? provenance
Measurement Clocks and synchronisation.

Accuracy depends on reference and synchronisation.

Clock

Reference and accuracy.

Clock source

The reference clock.

  1. Which clock or reference produced this time? provenance
  2. How accurate is it? measurement

Synchronisation

NTP, PTP, GNSS.

Synchronisation

How clocks agree.

  1. How are clocks synchronised? definition
  2. What is the maximum offset between systems? measurement
Use Scheduling and ordering.

Time coordinates people and systems.

Scheduling

Across zones.

Schedule

Schedule and zone handling.

  1. In which zone should this event be shown to each participant? action
  2. What happens at daylight saving changes? boundary

Ordering events

Causality in systems.

Ordering

How events are ordered.

  1. Can timestamps be trusted to order these events? boundary
  2. Is a logical clock needed? definition

What the second pass must settle

  • Should instants, durations and intervals be separate entries?
  • How should the registry require time zones on timestamps?
  • The registry entry has merged aliases such as paid time off; should they be split off?
Draft as JSON