TRISETCMP(1)

💖 TRISETCMP 💖

okay bestie so this is a page straight outta The Regina Handbook, section 1 of the manuals, and it's about a lil command called trisetcmp. yes it's a mouthful. no we're not renaming it. let's go ✨

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🌸 NAME 🌸

trisetcmp — compare triangulations between two Regina data files. that's the whole vibe. two files, triangulations, comparison. iconic behavior honestly 🎀

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🦋 SYNOPSIS 🦋

trisetcmp [ -m | -n ] [ -s ] file1 file2

trisetcmp { -v, --version | -?, --help }

like. that's it. that's the shape of it. two files go in, knowledge comes out 💅

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✨ DESCRIPTION ✨

so what this does is: it takes every triangulation in the first file and compares it against every triangulation in the second file, hunting for pairs of triangulations that are combinatorially isomorphic. it's giving matchmaker. it's giving wingman. it's giving "i know a guy" 🔥

both of the files you hand it must be Regina data files, no cap. it writes a full list of matches to standard output — or a full list of non-matches if you pass -n, because sometimes we're in our hater era.

a match happens when some triangulation from file1 is combinatorially isomorphic to some triangulation from file2. and what does that mean? it means they're identical up to a relabelling of tetrahedra and their vertices. same shape, different nametags. periodt 💖

this utility can also do subcomplex testing instead of full isomorphism testing. that's a whole different mode — peek at the -s option for the deets.

also: it compares both 3-manifold and 4-manifold triangulations (but no other dimensions at present, sorry to the 5D girlies 😭). and here's the thing — it will only compare triangulations of the same dimension. it will not test whether some 3-manifold triangulation appears as a subcomplex of some other 4-manifold triangulation. nope. not doing that. don't ask 🫶

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💅 OPTIONS 💅

• -m (default) — output matches only. every isomorphic match between triangulations in file1 and triangulations in file2 gets listed. this is the default, so if you say nothing, you get this. main character energy, no notes 👑
• -n — output non-matches only. every triangulation from file1 with no isomorphic match in file2 gets listed, and vice versa. both directions. the full receipts.

if -s is passed then non-matches are tested in one direction only, not both; see below for details. lowkey important, don't skip it 🙈

• -s — instead of testing triangulations for isomorphism, test whether one triangulation is isomorphic to a subcomplex of the other. like, is this one inside that one. tiny triangulation in a big triangulation's DMs 💀

in the default case of -m (output matches only), this program outputs all instances where a triangulation from file1 is isomorphic to a subcomplex of a triangulation from file2.

in the case of -n (output non-matches only), this program outputs all triangulations from file1 that are not isomorphic to a subcomplex of any triangulation from file2.

• -v, --version — show which version of Regina is being used, and exit immediately. quick lil flex, then it's gone 🌈
• -?, --help — display brief usage information, and exit immediately. the "help me bestie" button ⭐

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🌍 INTERNATIONALISATION 🌍

if any packets contain international characters, Regina will attempt to convert these to your local character encoding as it writes them to the output. it's trying its best, and honestly it's doing great 🧚

you can tell Regina what character encoding to use by setting standard locale-related environment variables, such as LANG, LC_CTYPE or LC_ALL.

for example: if LANG is set to en_AU then output will be written in the Western European character set ISO-8859-1, and if LANG is set to en_AU.UTF-8 then output will be written in the universal character set UTF-8. cute, right? 🌸

typically these environment variables will already be set for you when you install your GNU/Linux system, and Regina will just use the right character set out of the box. see your GNU/Linux system reference for further information on supporting different locales. iykyk 💜

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🍓 MACOS USERS 🍓

if you downloaded a drag-and-drop app bundle, this utility is shipped inside it. if you dragged Regina to the main Applications folder, you can run it as:

/Applications/Regina.app/Contents/MacOS/trisetcmp

it's literally just sitting in there waiting for you. slay 🎀

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🪟 WINDOWS USERS 🪟

the command-line utilities are installed beneath the Program Files directory; on some machines this directory is called Program Files (x86). you can start this utility by running:

c:\Program Files\Regina\Regina 7.4.1\bin\trisetcmp.exe

yes the path is long. yes it's giving haunted mansion hallway. but it works 💀✨

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👀 SEE ALSO 👀

censuslookup, regina-gui.

go read those too. they're also iconic. you're welcome 🫶

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💌 AUTHOR 💌

this utility was written by Benjamin Burton <bab@maths.uq.edu.au>. many people have been involved in the development of Regina; see the users' handbook for a full list of credits. legends, all of them 👑

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ok that's the whole page, bestie. go compare some triangulations. you got this. no cap 💖

sign-off szn — this came from The Regina Handbook, version Regina 7.4.1, dated 25 August 2025. mwah 💅🌸