Pedigree collapse¶

The reduction in a pedigree’s number of distinct ancestors when the same individual occupies multiple ancestral positions through shared descent.

Version: v1 · 2026-09-08 · History
Domain-specific #: 6023
Origin domain: genealogy
Subdomain: genealogy
Aliases: Implex, Ahnenschwund

Core Idea¶

It concerns repeated identities in ancestry rather than missing records, genetic inbreeding coefficients require additional path and meiosis information and generation counts are model-dependent. When two parents share an ancestor, their descendant’s nominal binary ancestry paths reconverge, so multiple slots in the pedigree refer to one historical person rather than distinct people. The abstraction is therefore identified by a declared carrier, a transformation or constraint over that carrier, and an invariant that tells an analyst whether the named structure is genuinely present.

Scope of Application¶

Pedigree collapse belongs to genealogy and is useful where the analyst can specify the typed genealogy carrier, including objects, relations, parameters, conventions, evidence, boundaries, and comparison targets, then evaluate the focal person, parent-child relations and generation depth, nominal ancestry slots, identity resolution of repeated ancestors, reconverging descent paths, distinct-person count, collapse amount or ratio and separation from documentary gaps and genetic relatedness measures are explicit. The scope is broad within that domain but bounded by the need for the focal person, parent-child relations and generation depth, nominal ancestry slots, identity resolution of repeated ancestors, reconverging descent paths, distinct-person count, collapse amount or ratio and separation from documentary gaps and genetic relatedness measures are explicit.

Clarity¶

The abstraction clarifies a crowded vocabulary by making the focal person, parent-child relations and generation depth, nominal ancestry slots, identity resolution of repeated ancestors, reconverging descent paths, distinct-person count, collapse amount or ratio and separation from documentary gaps and genetic relatedness measures are explicit the center of the account. A claim should name the carrier, the governing operation or relation, the applicable assumptions, and the recognition test.

Manages Complexity¶

Without the abstraction, an analyst must reason directly over many local details: the carrier roles, admissibility assumptions, competing conventions, derived invariants, boundary cases, and proof or validation obligations specific to Pedigree collapse. Pedigree collapse compresses them into the roles in the structural signature. That compression permits comparison across instances without erasing the variables that determine validity. It also exposes which details may be varied safely and which are constitutive.

Abstract Reasoning¶

Identify the carrier. State what the elements, states, objects, or observations are: the typed genealogy carrier, including objects, relations, parameters, conventions, evidence, boundaries, and comparison targets. Reject examples whose alleged carrier belongs to a different problem. 2. Lock the constitutive rule. Express the focal person, parent-child relations and generation depth, nominal ancestry slots, identity resolution of repeated ancestors, reconverging descent paths, distinct-person count, collapse amount or ratio and separation from documentary gaps and genetic relatedness measures are explicit independently of one notation or implementation.

Knowledge Transfer¶

Knowledge transfers strongly among subfields of genealogy because they reuse the typed genealogy carrier, including objects, relations, parameters, conventions, evidence, boundaries, and comparison targets, When two parents share an ancestor, their descendant’s nominal binary ancestry paths reconverge, so multiple slots in the pedigree refer to one historical person rather than distinct people., and type the carrier, state every parameter and convention in the definition, test that the focal person, parent-child relations and generation depth, nominal ancestry slots, identity resolution of repeated ancestors, reconverging descent paths, distinct-person count, collapse amount or ratio and separation from documentary gaps and genetic relatedness measures are explicit, compare the nearest accepted identity, and report counterexamples, uncertainty, and limiting cases.

Relationships to Other Abstractions¶

Current abstraction Pedigree collapse Domain-specific

Parents (1) — more general patterns this builds on

Pedigree collapse is a kind of Compression Prime

The proposed strict upward parent is prime:compression.

Hierarchy paths (3) — routes to 3 parentless roots

Pedigree collapse → Compression → Abstraction

Show alternative paths (2)

Neighborhood in Abstraction Space¶

Pedigree collapse sits in a moderately populated region (42^nd percentile for distinctiveness): it has near-neighbors but no dense thicket of look-alikes.

Family — Inheritance, Lineage & Development (17 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-09-08