Geometry of rational quasi-independence models as toric fiber products

Fuente: arXiv
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Main Authors: Coons, Jane Ivy, Harrington, Heather A., Paul, Niharika Chakrabarty
Format: Preprint
Published: 2024
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_version_ 1866917174360145920
author Coons, Jane Ivy
Harrington, Heather A.
Paul, Niharika Chakrabarty
author_facet Coons, Jane Ivy
Harrington, Heather A.
Paul, Niharika Chakrabarty
contents We investigate the geometry of a family of log-linear statistical models called quasi-independence models. The toric fiber product is useful for understanding the geometry of parameter inference in these models because the maximum likelihood degree is multiplicative under the TFP. We define the coordinate toric fiber product, or cTFP, and give necessary and sufficient conditions under which a quasi-independence model is a cTFP of lower-order models. We show that the vanishing ideal of every 2-way quasi-independence model with ML-degree 1 can be realized as an iterated toric fiber product of linear ideals. We also classify which Lawrence lifts of 2-way quasi-independence models are cTFPs and give a necessary condition under which a $k$-way model has ML-degree 1 using its facial submodels.
format Preprint
id arxiv_https___arxiv_org_abs_2405_13897
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Geometry of rational quasi-independence models as toric fiber products
Coons, Jane Ivy
Harrington, Heather A.
Paul, Niharika Chakrabarty
Algebraic Geometry
Combinatorics
Statistics Theory
62R01, 14M25, 62F30, 05C90
We investigate the geometry of a family of log-linear statistical models called quasi-independence models. The toric fiber product is useful for understanding the geometry of parameter inference in these models because the maximum likelihood degree is multiplicative under the TFP. We define the coordinate toric fiber product, or cTFP, and give necessary and sufficient conditions under which a quasi-independence model is a cTFP of lower-order models. We show that the vanishing ideal of every 2-way quasi-independence model with ML-degree 1 can be realized as an iterated toric fiber product of linear ideals. We also classify which Lawrence lifts of 2-way quasi-independence models are cTFPs and give a necessary condition under which a $k$-way model has ML-degree 1 using its facial submodels.
title Geometry of rational quasi-independence models as toric fiber products
topic Algebraic Geometry
Combinatorics
Statistics Theory
62R01, 14M25, 62F30, 05C90
url https://arxiv.org/abs/2405.13897