---
name: "censuslookup"
section: "1"
platform: "linux"
package: "regina"
version: "7.4.1-4"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/censuslookup"
---

# censuslookup(1)

Search for triangulations in Regina's census databases

## NAME

censuslookup - Search for triangulations in Regina's census databases

## SYNOPSIS

**censuslookup** *isosig ...*

**censuslookup** { **-v, --version** \| **-?, --help** }

## DESCRIPTION

This utility searches for the given 3-manifold triangulations in the various census databases that are shipped withRegina.

You should present the trianguations using their *isomorphism* *signatures*.  These are short text strings that identify the triangulation uniquely up to combinatorial isomorphism (i.e., up to relabellings of the tetrahedra and/or their vertices).

From the graphical user interface, you can view the isomorphism signature of a triangulation by switching to the Composition tab in the triangulation viewer.  From Python you can fetch the isomorphism signature of the triangulation **x** by calling **x.isoSig()**. For a full and precise specification of isomorphism signatures, see **Simplification paths in the Pachner graphs of closed** **orientable 3-manifold triangulations**, Burton, 2011, arXiv:1110.6080.

All database matches (if any) will be written to standard output.

## OPTIONS

- **-v, --version**

  Show which version of Regina is being used, and exit immediately.

- **-?, --help**

  Display brief usage information, and exit immediately.

## ENVIRONMENT VARIABLES

The following environment variables influence the behaviour of this program.

- *REGINA\_HOME*

  The directory beneath which Regina's data files are installed. This utility will look for the census databases in the subdirectory *$REGINA\_HOME/data/census/*.

  Normally you should not need to set this option yourself. This utility should know how to find its census databases in standard situations, which include fixed filesystem installations (e.g., **GNU/Linux** and **Windows**), relocatable app bundles (e.g., **macOS**), and running directly from the source tree.

## EXAMPLE

```
    example$ censuslookup fvPQcdecedekrsnrs dLQbcccajqs cPcbbbiht
    fvPQcdecedekrsnrs: 1 hit
        SFS [S2: (2,1) (3,1) (5,-4)] : #1 -- Closed census (orientable)
    dLQbcccajqs: 0 hits
    cPcbbbiht: 2 hits
        m004 : #1 -- Cusped hyperbolic census (orientable)
        L104001 -- Hyperbolic knot and link complements
    example$
```

## 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/censuslookup.

## 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\\censuslookup.exe.

## SEE ALSO

regina-gui. trisetcmp,

## 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.