REVIEW 2 minor 83 references
Interval hypergraphic polytopes (or deformed associahedra), Tamari interval posets, and weeping willows
T0 review · 0 major / 2 minor · reviewed 2026-06-26 · grok-4.3
Pith's one-line read Interval hypergraphs on [n] produce polytopes whose vertex posets are Tamari interval posets, with the simple cases having weeping willow posets.
desk verdict The paper gives explicit bijections showing interval hypergraphic polytopes have Tamari interval posets as vertex posets, with weeping willows for the simple cases. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The explicit mapping from interval hypergraphs (hyperedges restricted to intervals of [n]) to Tamari interval posets realized as the vertex posets of the corresponding Minkowski-sum polytopes.
What would settle it
An explicit interval hypergraph on a small n whose computed vertices do not form a Tamari interval poset, or a simple interval hypergraphic polytope whose vertex poset is not a weeping willow.
Extended reading notes
Core claim
For any interval hypergraph on [n], the associated hypergraphic polytope is a deformation of Loday's associahedron whose vertex poset is a Tamari interval poset. The interval hypergraphs for which this polytope is simple have vertex posets that are weeping willows.
Load-bearing premise
Restricting hyperedges to intervals on [n] is enough to guarantee that the hypergraphic polytope deforms Loday's associahedron and that its vertices correspond to Tamari interval posets.
Editorial extensions
If this is right
- Every choice of interval hypergraph on [n] yields a hypergraphic polytope whose vertices are labeled by a Tamari interval poset.
- The simple interval hypergraphic polytopes are precisely those whose vertex posets belong to the weeping willow family.
- Different interval hypergraphs produce different Tamari interval posets as their vertex posets.
- The geometric properties of the polytope, such as simplicity, translate directly into combinatorial restrictions on the corresponding Tamari interval poset.
Reading between the lines
- The construction supplies a geometric model in which combinatorial operations on Tamari interval posets can be studied via Minkowski sums and face lattices of polytopes.
- One could test whether non-interval hypergraphs ever produce Tamari interval posets or whether the interval restriction is necessary for the correspondence.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper defines interval hypergraphic polytopes as Minkowski sums of standard simplices over interval hyperedges on [n]. It establishes that these are precisely the deformations of Loday's associahedron, proves that their vertex posets coincide with Tamari interval posets via explicit bijections, describes the correspondence between specific interval hypergraphs and Tamari interval posets, characterizes the interval hypergraphs yielding simple polytopes, and names the vertex posets of the simple cases 'weeping willows'.
Significance. If the explicit bijections and characterizations hold as described, the work supplies a direct combinatorial link between hypergraphic polytopes, deformations of the associahedron, and Tamari interval posets. The step-by-step development from the Minkowski-sum definition to the poset identifications strengthens the contribution to algebraic combinatorics and polytope theory.
minor comments (2)
- The abstract and introduction would benefit from a brief statement of the main theorem numbers that establish the bijection between vertices and Tamari interval posets.
- Notation for the interval hypergraph I and the resulting polytope triangle_I is introduced early; a consolidated table of symbols in an appendix would aid readability.
Simulated Author's Rebuttal
We thank the referee for their positive summary of the manuscript and for recommending minor revision. No specific major comments were raised in the report.
Circularity Check
No significant circularity; derivation self-contained from Minkowski sums and poset definitions
full rationale
The paper defines hypergraphic polytopes via Minkowski sums of simplices over interval hypergraphs, then proves (via explicit bijections and characterizations in the full manuscript) that their vertex posets are Tamari interval posets and identifies the simple cases as weeping willows. No step reduces a claimed result to a fitted parameter, self-citation load-bearing premise, or definitional renaming; the identifications follow from combinatorial constructions starting from the Minkowski-sum definition without circular reduction. The abstract's statements are supported by step-by-step proofs rather than presupposing the conclusions.
Assumptions & free parameters
assumptions (1)
- standard math Minkowski sum of simplices yields a polytope whose vertices correspond to selections of one vertex from each summand
invented entities (1)
-
weeping willows
Cite this review
Pith. "Pith review of Interval hypergraphic polytopes (or deformed associahedra), Tamari interval posets, and weeping willows." pith.science (2026). https://pith.science/paper/MWKSCCQD
@misc{pith2026260618376,
author = {Pith},
title = {Pith review of: Interval hypergraphic polytopes (or deformed associahedra), Tamari interval posets, and weeping willows},
year = {2026},
howpublished = {\url{https://pith.science/paper/MWKSCCQD}},
note = {Machine review of arXiv:2606.18376}
}
abstract
For a hypergraph $\mathbb{H}$ on $[n]$, the hypergraphic polytope $\triangle_{\mathbb{H}}$ is the Minkowski sum of the standard simplices $\triangle_H$ for all $H \in \mathbb{H}$. We focus here on interval hypergraphs, where all hyperedges are intervals of $[n]$. They are precisely the deformations of Loday's associahedron. Their vertex posets are Tamari interval posets, and we describe which Tamari interval poset appears as a vertex poset in which interval hypergraphic polytope. We also characterize the interval hypergraphs $\mathbb{I}$ for which the hypergraphic polytope $\triangle_\mathbb{I}$ is simple, and we study their vertex posets, which we call weeping willows.
Figures
Figures from the paper (14 more)
Reference graph
Works this paper leans on
-
[1]
Postnikov, Alexander , TITLE =. Int. Math. Res. Not. IMRN , FJOURNAL =. 2009 , NUMBER =
2009
-
[2]
, TITLE =
Postnikov, Alexander and Reiner, Victor and Williams, Lauren K. , TITLE =. Doc. Math. , FJOURNAL =. 2008 , PAGES =
2008
-
[3]
Combinatorial
Edmonds, Jack , TITLE =. Combinatorial
-
[4]
Feichtner, Eva Maria and Sturmfels, Bernd , TITLE =. Port. Math. (N.S.) , FJOURNAL =. 2005 , NUMBER =
2005
-
[5]
Benedetti, Carolina and Bergeron, Nantel and Machacek, John , TITLE =. J. Comb. , FJOURNAL =. 2019 , NUMBER =
2019
-
[6]
European J
Bergeron, Nantel and Pilaud, Vincent , TITLE =. European J. Combin. , FJOURNAL =. 2026 , PAGES =
2026
-
[7]
Discrete Comput
Pilaud, Vincent and Poullot, Germain , TITLE =. Discrete Comput. Geom. , FJOURNAL =
-
[8]
and Devadoss, Satyan L
Carr, Michael P. and Devadoss, Satyan L. , TITLE =. Topology Appl. , FJOURNAL =. 2006 , NUMBER =
2006
Show all 83 references
-
[9]
Algebra Universalis , FJOURNAL =
Barnard, Emily and McConville, Thomas , TITLE =. Algebra Universalis , FJOURNAL =. 2021 , NUMBER =
2021
-
[10]
and Pitman, Jim , TITLE =
Stanley, Richard P. and Pitman, Jim , TITLE =. Discrete Comput. Geom. , FJOURNAL =. 2002 , NUMBER =
2002
-
[11]
Topology Appl
Saneblidze, Samson , TITLE =. Topology Appl. , FJOURNAL =. 2009 , NUMBER =
2009
-
[12]
Pilaud, Vincent and Poliakova, Daria , TITLE =. Math. Ann. , FJOURNAL =. 2025 , NUMBER =
2025
-
[13]
Discrete Comput
Defant, Colin , TITLE =. Discrete Comput. Geom. , FJOURNAL =. 2023 , NUMBER =
2023
-
[14]
Pilaud, Vincent , TITLE =. Ann. Comb. , FJOURNAL =
-
[15]
Discrete Comput
Kim, Sangwook , TITLE =. Discrete Comput. Geom. , FJOURNAL =. 2008 , NUMBER =
2008
-
[16]
Permutation statistics and linear extensions of posets , VOLUME =
Bj. Permutation statistics and linear extensions of posets , VOLUME =. J. Combin. Theory Ser. A , NUMBER =
-
[17]
Algebraic Combinatorics , PUBLISHER =
Chatel, Gr\'egory and Pilaud, Vincent and Pons, Viviane , TITLE =. Algebraic Combinatorics , PUBLISHER =. 2019 , PAGES =
2019
-
[18]
Counting smaller elements in the
Ch. Counting smaller elements in the. J. Combin. Theory Ser. A , Pages =
-
[19]
Sur le nombre d'intervalles dans les treillis de
Chapoton, Fr\'. Sur le nombre d'intervalles dans les treillis de. S\'. 2005/07 , PAGES =
2005
-
[20]
Une note sur les intervalles de
Chapoton, Fr\'. Une note sur les intervalles de. Ann. Math. Blaise Pascal , FJOURNAL =. 2018 , NUMBER =
2018
-
[21]
Bernardi, Olivier and Bonichon, Nicolas , TITLE =. J. Combin. Theory Ser. A , FJOURNAL =. 2009 , NUMBER =
2009
-
[22]
Tamari intervals and blossoming trees , JOURNAL =
Fang, Wenjie and Fusy, \'. Tamari intervals and blossoming trees , JOURNAL =. 2025 , NUMBER =
2025
-
[23]
Schoute, Pieter Hendrik , TITLE =
-
[24]
Rado, Richard , TITLE =. J. London Math. Soc. , FJOURNAL =. 1952 , PAGES =
1952
-
[25]
Celebrating
Pilaud, Vincent and Santos, Francisco and Ziegler, G\". Celebrating. Arch. Math. (Basel) , FJOURNAL =. 2023 , NUMBER =
2023
-
[26]
Tamari, Dov , TITLE =
-
[27]
Loday, Jean-Louis , TITLE =. Arch. Math. (Basel) , FJOURNAL =. 2004 , NUMBER =
2004
-
[28]
Operads:
Tonks, Andy , TITLE =. Operads:
-
[29]
1993 , PAGES =
Shnider, Steve and Sternberg, Shlomo , TITLE =. 1993 , PAGES =
1993
-
[30]
Reading, Nathan , TITLE =. SIAM J. Discrete Math. , FJOURNAL =. 2015 , NUMBER =
2015
-
[31]
Order , FJOURNAL =
Reading, Nathan , TITLE =. Order , FJOURNAL =. 2004 , NUMBER =
2004
-
[32]
Reading, Nathan , TITLE =. Adv. Math. , FJOURNAL =. 2006 , NUMBER =
2006
-
[33]
Pilaud, Vincent and Santos, Francisco , TITLE =. Bull. Lond. Math. Soc. , FJOURNAL =. 2019 , VOLUME =
2019
-
[34]
Padrol, Arnau and Pilaud, Vincent and Ritter, Julian , TITLE =. Int. Math. Res. Not. IMRN , FJOURNAL =. 2023 , NUMBER =
2023
-
[35]
European J
Pilaud, Vincent and Santos, Francisco , TITLE =. European J. Combin. , FJOURNAL =. 2012 , NUMBER =
2012
-
[36]
Geometriae Dedicata , FJOURNAL =
McMullen, Peter , TITLE =. Geometriae Dedicata , FJOURNAL =. 1973 , PAGES =
1973
-
[37]
Padrol, Arnau and Palu, Yann and Pilaud, Vincent and Plamondon, Pierre-Guy , TITLE =. Proc. London Math. Soc. , FJOURNAL =. 2023 , NUMBER =
2023
-
[38]
European J
Padrol, Arnau and Pilaud, Vincent and Poullot, Germain , TITLE =. European J. Combin. , FJOURNAL =. 2023 , PAGES =
2023
-
[39]
Electron
Albertin, Doriann and Pilaud, Vincent and Ritter, Julian , TITLE =. Electron. J. Combin. , FJOURNAL =. 2021 , NUMBER =
2021
-
[40]
Bazier-Matte, V\'eronique and Chapelier-Laguet, Nathan and Douville, Guillaume and Mousavand, Kaveh and Thomas, Hugh and Y. J. Lond. Math. Soc. (2) , FJOURNAL =. 2023 , DOI =
2023
-
[41]
1970 , PAGES =
Stasheff, James , TITLE =. 1970 , PAGES =
1970
-
[42]
1997 , publisher=
Enumerative Combinatorics: Volume 1 , author=. 1997 , publisher=
1997
-
[43]
Topology Appl
Forcey, Stefan , TITLE =. Topology Appl. , FJOURNAL =. 2008 , NUMBER =
2008
-
[44]
Homology Homotopy Appl
Saneblidze, Samson and Umble, Ronald , TITLE =. Homology Homotopy Appl. , FJOURNAL =. 2004 , NUMBER =
2004
-
[45]
Ardila, Federico and Doker, Jeffrey , TITLE =. Adv. in Appl. Math. , FJOURNAL =. 2013 , NUMBER =
2013
-
[46]
Shuffles of deformed permutahedra, multiplihedra, constrainahedra, and biassociahedra , JOURNAL =
Chapoton, Fr\'. Shuffles of deformed permutahedra, multiplihedra, constrainahedra, and biassociahedra , JOURNAL =. 2024 , PAGES =
2024
-
[47]
Bottman, Nathaniel and Poliakova, Daria , TITLE =
-
[48]
Source characterization of the hypergraphic posets , NOTE =
G. Source characterization of the hypergraphic posets , NOTE =
-
[49]
Aguiar, Marcelo and Ardila, Federico , TITLE =. Mem. Amer. Math. Soc. , FJOURNAL =. 2023 , NUMBER =
2023
-
[50]
Discrete Comput
Padrol, Arnau and Pilaud, Vincent and Poullot, Germain , TITLE =. Discrete Comput. Geom. , FJOURNAL =. 2025 , NUMBER =
2025
-
[51]
Padrol, Arnau and Pilaud, Vincent and Poullot, Germain , TITLE =. S\'. 2022 , PAGES =
2022
-
[52]
Electron
Rehberg, Sophie , TITLE =. Electron. J. Combin. , FJOURNAL =. 2022 , NUMBER =
2022
-
[53]
and Merino, Arturo and Mi
Cardinal, Jean and Hoang, Hung P. and Merino, Arturo and Mi. Combinatorial generation via permutation languages. SIAM J. Discrete Math. , FJOURNAL =. 2023 , NUMBER =
2023
-
[54]
Cardinal, Jean and Steiner, Raphael , TITLE =. Comb. Theory , FJOURNAL =. 2025 , NUMBER =
2025
-
[55]
, TITLE =
Agnarsson, Geir and Morris, Walter D. , TITLE =. Ann. Comb. , FJOURNAL =. 2009 , NUMBER =
2009
-
[56]
Electron
Agnarsson, Geir , TITLE =. Electron. J. Combin. , FJOURNAL =. 2017 , NUMBER =
2017
-
[57]
Ornamentation lattices and intreeval hypergraphic lattices , NOTE =
Abram, Antoine and Bastidas, Jose and G. Ornamentation lattices and intreeval hypergraphic lattices , NOTE =
-
[58]
Proceedings of the NATO Advanced Study Institute held in Berlin (West Germany) , SERIES =
Greene, Curtis , TITLE =. Proceedings of the NATO Advanced Study Institute held in Berlin (West Germany) , SERIES =
-
[59]
Greene, Curtis and Zaslavsky, Thomas , TITLE =. Trans. Amer. Math. Soc. , FJOURNAL =. 1983 , NUMBER =
1983
-
[60]
, TITLE =
Stanley, Richard P. , TITLE =. Discrete Math. , FJOURNAL =. 1973 , PAGES =
1973
-
[61]
Selecta Math
De Concini, Conrado and Procesi, Claudio , TITLE =. Selecta Math. (N.S.) , FJOURNAL =. 1995 , NUMBER =
1995
-
[62]
Hypergraph polytopes , JOURNAL =
Do. Hypergraph polytopes , JOURNAL =. 2011 , NUMBER =
2011
-
[63]
Pilaud, Vincent , TITLE =
-
[64]
Knutson, Allen and Miller, Ezra , TITLE =. Adv. Math. , FJOURNAL =. 2004 , NUMBER =
2004
-
[65]
Knutson, Allen and Miller, Ezra , TITLE =. Ann. of Math. (2) , FJOURNAL =. 2005 , NUMBER =
2005
-
[66]
Discrete Geometry and Optimization , PUBLISHER =
Pilaud, Vincent and Stump, Christian , TITLE =. Discrete Geometry and Optimization , PUBLISHER =. 2013 , PAGES =
2013
-
[67]
European J
Froese, Vincent and Renken, Malte , TITLE =. European J. Combin. , FJOURNAL =. 2024 , PAGES =
2024
-
[68]
Discrete Math
Dumont, Dominique and Randrianarivony, Arthur , TITLE =. Discrete Math. , FJOURNAL =. 1994 , NUMBER =
1994
-
[69]
On grounded
Jel\'. On grounded. Electron. J. Combin. , FJOURNAL =. 2019 , NUMBER =
2019
-
[70]
Proceedings of the 35th European Workshop on Computational Geometry (EuroCG) , PAGES =
Ashur, Stav and Filtser, Omrit and Sababn, Rachel , TITLE =. Proceedings of the 35th European Workshop on Computational Geometry (EuroCG) , PAGES =
-
[71]
Discrete Comput
Froese, Vincent and Renken, Malte , TITLE =. Discrete Comput. Geom. , FJOURNAL =. 2021 , NUMBER =
2021
-
[72]
Hixon, Thomas Stuart , TITLE =
-
[73]
Discrete Math
Soto, Mauricio and Thraves Caro, Christopher , TITLE =. Discrete Math. Theor. Comput. Sci. , FJOURNAL =. 2015 , NUMBER =
2015
-
[74]
Max point-tolerance graphs , JOURNAL =
Catanzaro, Daniele and Chaplick, Steven and Felsner, Stefan and Halld\'. Max point-tolerance graphs , JOURNAL =. 2017 , NUMBER =
2017
-
[75]
Involve , FJOURNAL =
Clark, Tyler and Richmond, Tom , TITLE =. Involve , FJOURNAL =. 2015 , NUMBER =
2015
-
[76]
2026 , eprint=
Indecomposability and beyond via the graph of edge dependencies , author=. 2026 , eprint=
2026
-
[77]
2025 , eprint=
Rays of the deformation cones of graphical zonotopes , author=. 2025 , eprint=
2025
-
[78]
, TITLE =
Wilf, Herbert S. , TITLE =. 1986 , PAGES =
1986
-
[79]
Electron
Bostan, Alin and Chyzak, Fr\'ed\'eric and Pilaud, Vincent , TITLE =. Electron. J. Combin. , FJOURNAL =. 2026 , NUMBER =. doi:10.37236/14666 , URL =
2026 doi
-
[80]
Dermenjian, Aram and Hohlweg, Christophe and Pilaud, Vincent , TITLE =. Trans. Amer. Math. Soc. , FJOURNAL =. 2018 , NUMBER =. doi:10.1090/tran/7307 , URL =
2018 doi
-
[81]
2026 , eprint=
Dyck Paths, Configuration Spaces and Polytopes For Linear Nakayama algebras , author=. 2026 , eprint=
2026
-
[82]
Arkani-Hamed, Nima and Bai, Yuntao and He, Song and Yan, Gongwang , TITLE =. J. High Energy Phys. , FJOURNAL =. 2018 , NUMBER =. doi:10.1007/jhep05(2018)096 , URL =
2018 doi
-
[83]
2026 , eprint=
Many rays of the submodular cone , author=. 2026 , eprint=
2026
Reviewed June 26, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.