Chapter 12, Appendix |Population Migration Section 1 | Southward and Westward Expansion of the North China Population (Including Luxi)

This section primarily discusses the southward and westward migration of the North China population (including Luxi) during MIS 4–2(71–11 ka).It serves as a supplementary argument within the LSED system's Chapter 12(World Verdict on Populations)regarding population migration. The narrative starting point is the Phase Transition Position(Luxi,71–57 ka).This is an“intra-system conclusion”and“framework inference”,rather than an empirically excavated fact.The expansion outward from the Phase Transition Position focuses on“starting conditions”and the“convergence relationships of external populations”, constituting a macroscopic analysis of areal regional density. I.Four Parallel Statements The entire section presents four parallel statements based on“evidence type”(not time period,not geographic location),with time and location annotated simultaneously for each: Segment A | Phase Transition PositionEvidence type:Intra-system conclusion;Time:71–57 ka;Location:Luxi.Segment B | Modern Human–Neanderthal Gene FlowEvidence type:Genetic evidence;Time:50–40 ka;Location:Eurasian Steppe Corridor (non-overlapping with the Phase Transition Position). Segment C | Mousterian Technological Influence in NihewanEvidence type:Archaeological evidence;Time:95–81 ka;Location:Nihewan. Segment D | The Nihewan–Luxi RouteEvidence type:Framework inference;Time:Prior to the Phase Transition window(71–57 ka);Location:Nihewan→Luxi. The four segments are mutually independent,do not serve as premises for one another,and do not form a causal chain. II.Three Parallel Tiers Beyond the four segments,this section establishes three parallel tiers(parallel to the four segments,mutually independent): 1.5.3 | Testable Conditions for Neanderthal Influence in North China Nature:Condition registry;no inference proposed;Content:Only registers Conditions A/B/C and their trigger status;Current status:All three conditions remain untriggered;untriggered status constitutes neither falsification nor support for any direction. 1.5.4 | Archaeological Layer Population Density Survey Nature:Independent archaeological survey;not related to the M122 lineage tier,nor to origin determination;Standard:A three-tier standard(High/Medium/Dispersed)registered in advance,with data source Ge et al.2024;Layer constraint:Beixin-Dawenkou materials(ca.7–5 ka)are marked as“Holocene reference,not participating in MIS 4–2 determination”. 1.5.5 | Structural Plausibility Judgment Nature:Agenda tier,not determination tier;Strength:“Structurally plausible”does not equal“structurally inevitable”;Dependency:Methodological premise(Phase Transition Position in Luxi);positive materials pending verification;Evidence admission:Based solely on MIS 4–2 ancient DNA and archaeological materials;excludes southern Holocene samples and modern DNA;Boundary:Does not constitute input to the determination tier,nor does it alter the determination status of Segments A/B/C/D. III.Westward Migration Three-Tier Structure(1.9) The westward migration section(1.9)adopts a three-tier structure(tiers are discrete and do not derive from one another): Tier 1 | Background LayerTechnology:IUP blades;Time:MIS 3;Direction:West→East;Role:Literature is complete;non-primary claim,nor does it constitute counter-evidence against the primary claim. Tier 2 | Candidate LayerTechnology:North China microblade↔Altai southward migration;Time:MIS 2;Direction:Bidirectional controversy;Status:West 1–West 4,all four segments“?”. Tier 3 | Primary ClaimTime:MIS 2;Direction:East→West(from Phase Transition Position westward);Authorization:Directional premise authorized by the Default Clause;does not automatically establish via Tier 2. Inter-tier relationship:Tier 2 is not evidence for Tier 3;Tier 3 is not the conclusion of Tier 2.Terminology lock:IUP blades/bladelet/microblade are locked in 1.9.1 and are not interchangeable. IV.Pre-registration and Procedural Clauses This section establishes bidirectional pre-registration(P1-1 to P1-8):upgrading and downgrading conditions are parallel,registered in advance to prevent post hoc directional selection. The five PBR-4 parameters(survey site density,sample size,detection limit,determination criteria,registration date)were registered on 2026-10-15;the downgrading side is“registered,not executed”. This section also establishes the Default Clause(Direction)as a procedural inference clause:authorization is limited to the directional premise of the specific claim“from the Phase Transition Position,MIS 2,North China microblade tradition”;reverse layers are not authorized;direction cannot be reversed. V.Boundaries This section makes no origin determination throughout.The four segments,three tiers,and westward three-tier structure are mutually independent,with conclusions non-derivative. Registration and uncertainty annotation of modern DNA data are detailed in Appendix I·Appendix A(Registry Section,not participating in determination).