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Research draft

sequence

vr.tr.sequence · XCT.QLT

Let an agent treat a sequence as an ordered structure with an index, a length and a rule, and separate order-bearing sequences from unordered collections.

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 treat a sequence as an ordered structure with an index, a length and a rule, and separate order-bearing sequences from unordered collections.

An ordered succession of items, events or elements, in which order matters; in mathematics, a function from the natural numbers (or an initial segment of them) to a set.

What it is for: Representing order: steps of a procedure, events in time, terms of a series, symbols in a string.

It can be index and traverse it; define it, by a rule or by listing; test properties, such as convergence or monotonicity; reorder it, which changes what it is.

Distinguishing features

Order matters, unlike a set

Repetition allowed, unlike a set

Finite or infinite

A series is the sum of a sequence, not the sequence

What it looks like

A list written in order, a timeline, a numbered procedure, or a string of symbols.

How it is recognised

Items in a fixed order, often numbered

Mathematical notation such as (a_n)

Ritual or procedural sequences are sequences of steps

Related models

is confused with - sets are unordered

set

is confused with - a series sums terms

series

is used in - ordered steps and events

procedure and timeline

has kind - biological sequences

DNA or protein sequence

In practice

Families and kinds

finite and infinite sequences

arithmetic and geometric sequences

sequences of events and procedures

strings and biological sequences

Identifiers

OEIS A-number A followed by six digits integer sequences

Standards and regulation

ISO 80000-2 notation for sequences

Domain standards for procedures, such as BPMN for process sequences

Failure modes and hazards

Off-by-one indexing errors

Order lost when stored as a set

Assuming convergence without proof

Also called

rituals of the sweat lodgeMiyamairieruvmaypolerosary pathcascadestratigraphic seriesHY-2priestly ordinationsubdiaconal ordinationdiaconal ordinationseba Baduynuclear test seriespriestly ordination in the Roman ritediaconal ordination in the Roman ritegraphics pipelinetiled renderingslide deckWhite papertime seriesregularly spaced time seriesgeographical time seriesdeath knellseries of missionsbiological sequenceorder of successionliststandard inputprimary structureamino acid sequencetelomere lengthoutronPorphyrogenituresuccession to a peerageCEO successionArgentine presidential line of successiondemise of the Crownstratigraphic classification schemeOpenStreetMap wayOpenStreetMap relation

+636

Where this came from

wikidata · CC0 1.0

Source repository Registry entry point

Also registered as vr.tr.sequence-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.

Structure Index, length, elements.

A sequence is defined by its index set and elements.

Index

Starting point and range.

Indexing

The index convention.

  1. Does indexing start at 0 or 1, and how long is the sequence? definition
  2. Is it finite or infinite? definition

Elements

What the items are.

Element type

The type of elements.

  1. What kind of items does the sequence contain? definition
  2. Are repeats allowed? boundary
Rule How it is generated.

Rules make sequences predictable.

Definition

Formula or recurrence.

Rule

The generating rule.

  1. What rule generates the sequence? definition
  2. Is it listed in a reference such as OEIS? provenance

Properties

Monotonic, bounded, convergent.

Properties

Mathematical properties.

  1. Is the sequence monotonic, bounded or convergent? measurement
  2. What is its limit, if any? measurement
Order in practice Procedures and events.

In practice, sequences are steps and events whose order has consequences.

Procedure

Steps in order.

Step order

The required order.

  1. Which steps must happen in which order? definition
  2. What happens if the order is changed? boundary

Events

Chronology.

Chronology

The order of events.

  1. In what order did these events occur, according to which source? provenance
  2. How certain is the ordering? measurement
Storage Keeping order in data.

Data systems lose order unless it is stored explicitly.

Representation

Arrays, lists, strings.

Representation

How it is stored.

  1. How is the sequence stored so order is preserved? definition
  2. What is the cost of access by index? measurement

Errors

Off-by-one and reordering.

Error checks

Checks against errors.

  1. How are indexing errors prevented? action
  2. Could a sort have changed the order unintentionally? boundary

What the second pass must settle

  • Should mathematical, procedural and biological sequences be separate entries?
  • The registry entry has merged aliases such as rituals and stratigraphic series; should they be split off?
  • How should indexing conventions be recorded?
Draft as JSON