OpenMathMap: Interaction
Carmela Acevedo, Michael Kohlhase
Jacobs University Bremen

Abstract. Mathematics is a fast growing discipline where an average of
120 thousand papers are published per year. We seek to provide betterinterfaces to interact with this huge collection of documents. To study
new techniques that allow users to intuitively assess and interact withmathematical publication collections we use OpenMathMap (OMM) – a
computer-generated map which represents Mathematical Subject Classifications (MSC) class as “countries”, “states”, and “cities”. We present
a platform that allows to build interactions with semantical meta-data
based on OMM and show a variety of information services taking advantage of the semantic and hierarchical properties of the dataset at hand.
We evaluate the platform to determine how successful the map is as an
intuitive complement for search. The map proved to be a useful interface for interacting with and understanding the results that were being
displayed.

1

Introduction

We currently live in the times of big data. It has become a great challenge forhumans to discern information that interests them. Currently the most common
tool for going through a large amount of data are search engines. These systems
provide results organized by how relevant they are without considering the relationship between them. Grouping the results by a common topic could guidethe users to interpret them and provide an overview of the underlying structureof the information.
Organizing search results brings two challenges to the surface. One of them is
how to organize objects hierarchically in a way that provides a better overview
of the entire set of search than by listing them individually. The second challenge
is to visualize and display this information so that it is intuitive enough to guidethe user to discover new connections between results by diving into a topic ofinterest. Maps could be a potential answer to these problems. People are familiar
with maps from a young age. We learn how to read and navigate them. They
display the geographical world in a global, hierarchical way and at the sametime help us comprehend our surroundings. Having global and local information
simultaneously provides the information context. We will investigate whether amap can provide a hierarchical overview of non-geographical information thatwould promote discovery and investigation.
In the last fifteen years there have been an average of more than 120 thousand
publications in mathematics per year [Zen13a]. The last version of the Mathematical Subject Classification (MSC [MSC12]) has been decided upon jointlybetween Mathematical Reviews (MR) and Zentralblatt für Mathematik (Zbl).
All publications have been assigned a main MSC class they belong to and anumber of secondary classes related to it. With this information a map of mathematics was generated. This is a good opportunity to research the possibility ofusing this map to retrieve information related to these publications. The OpenMathMap contains all first and second level MSC classes while showing how
they relate to each other[DKL13; DK13; Dör13]. We seek to take advantage ofthe fact that two classes that are close to each other contain publications thatare related. This interactive platform could serve as an overview for users tonavigate and discover information.
We will study the use of the interactive map as a tool for a semantic approachto search. To illustrate this we consider the scenario of a student that is undecided
as to what to focus on later on in her career in mathematics. She wants to be able
to narrow down her choices to a handful. For this she needs information about
which areas are thriving at the moment, what they are about and which authors
are active in them. We will evaluate how integrating interactive features to themap facilitate information retrieval in order to answer these specific questions.
Finally, we prove that by using maps for search the user gains more information
about the global topic and at the same time finds answer more easily. The current
state of the map and further information can be found at http://map.mathweb.
org.

2State of the art

The Paperscape project uses maps to visualize the arXiv dataset. Each circle intheir map represents one paper [GK14]. The distance between them is related
to how similar they are, the size of each circle is directly related to how manycitations each specific publication has.
Dave Rusin created a Math Atlas in the year 2000 [Rus02]. This atlas shows a circle for each of Zentralblatt’s MSC classes [MAT14]. These
have a size depending on the amountof papers published in them. They
are positioned according to their relation to the rest of the other categories(Fig. 1). The distance between classes
is directly related to how many papers have been published under bothcategories. This is an almost purely
Fig. 1: Rusin’s Math Atlas [Rus01]
visual representation of mathematics.
The only possible interaction with themap is clicking each circle which redirects the user to another page describing
the corresponding MSC class.

A similar attempt to Rusin’s is done by the OpenMathMap project. It uses
the Zentralblatt dataset to display all of the MSC classes including their similarity and amount of publications.

3

Preliminaries

In the scope of this project we are dealing with mathematical publications. All
the data was provided by Zentralblatt and it was later put together into one
cohesive system with the aid of mapping tools.
Zentralblatt is a service that provides reviews and publication content frompure and applied mathematics [Wik13; Zen13b]. It contains a comprehensive
database of all mathematical publications dating from 1755 which contains morethan 3 million bibliographical entries. In order to keep an organized structure ofthese publications they have decided upon a Mathematical Subject Classification jointly with the Americans Mathematical Society’s Mathematical Review.
Each published paper is given a primary MSC class and several accompanying
secondary classes.
Zentralblatt’s portal provides the opportunity to search their database. However, this search does not take advantage of the relationship between its results.
We are seeking to provide an interface that will give a visualization of such
results.

4

Scenario and Use Cases

We will focus our research on one specific scenario from which we develop threeuse cases. The goal is to evaluate whether a map is a viable search tool.
4.1

Scenario

We consider a mathematics student, Stephanie. She is looking to find more
information about the master’s programs she is admitted to. There is a set of
subjects she would like to study but she wants to know which is the most current.
Since she is very interested in research she wants to know how these places rankin publications. It is important for her that the respective departments and theirauthors are active in the topics she wants to focus on.
From this scenario we extract three use cases that we will be focusing on:
4.2

Current Areas of Mathematics

She wants to know which areas of mathematics are publishing the most in thepast years. The OpenMathMap provides the backbone to display all of thisinformation at once. We will solve this problem by providing an overlay to themap that shows how active areas of mathematics currently are.

4.3

Relevant author’s information

The map can be used to provide author’s information in a similar way as before.
By providing an overlay to the map that displays this information she could lookat it all at once and analyze it better.
4.4

Result filtering using semantic information

To investigate about the topics she is interested in she searches for publications.
The results of a search can be displayed on the map to show a general distributionof them. Knowing the geographical location of the classes can further help filter
results that are of special interest.

5

Use cases implementation

In order to reach a platform that provides the mentioned use cases we have tostart by developing some basic services.
We started with a tile map being served by a Javascript framework [Lea14].
We obtain the OpenStreetMap (OSM) [OSM14] XML file that was used to generate the map. This file contained all the countries’ boundaries and is uploaded
to a geometrical database (PostGIS) [Pos14]. This database provides tools forfinding the intersection between two points and the centroid of a polygon which
are extensively used later. At the current state of the system it is enough togenerate a new OSM file and upload it to the database in order to reuse it for
a newly generated map. This database also contains information about MSC
classes and authors obtained from the Zentralblatt dataset.
After having this available and being served by a framework (Django in thiscase) we create navigation opportunities for the user. The user can click a point
to know which country it belongs to. Searching can also be done under thefollowing categories: author, class and formula or text in a paper’s abstract.
Search results from all these modes result in markers appearing on the map.
Each marker when clicked launches a popup with the title of the marker and alink to the Zentralblatt page displaying the result. These markers are positioned
in the centroid of the class they belong to.
The information provided by the search is retrieved from the database in allcases except of the formula search. In this case we use a service provided byZentralblatt which allows for the search of formula’s in LATEXformat and text in
abstracts or titles of publications.
To show the current areas of mathematics (4.2) we use an overlay on themap. The coloring provides an extra degree to the map with more information.
Values are interpolated between red (‘#ff000’) and yellow (‘#ffff00’) mapped
between 0 and 100 respectively. The number that is provided for each class issomething that we had to investigate. It was necessary to narrow down theinformation about the year of publication in each class to a single number.
We have to pick a value that is related to the change in publication behavior
over time. At first we picked the average year of publication per class. This,(a) Normalizing with maximum(b) Normalizing without outliersFig. 2: Normalizing values considering outliers.

however, could have the problem that classes with very different behavior had thesame average. Then we tried to use the maximum which did not provide enoughdifferent values. Finally we decided on comparing the amount of publications thathave occurred in a class during the last 5 years with the rest of the publications.
We calculate the percentage that this amount represents which offers an insighton how active this class is compared to the past.
Since we scale all values between the minimum and the maximum outliers area problem, concentrating values in the mid range. Because of this we disregard
them and color them as either the minimum or the maximum (Fig. 2)
A single marker symbolizing an author is not enough to encode their trajectory throughout time (4.3). We are already positioning the marker on the classfor which the author has contributed the most. Each author can display two
different overlays.
The “Classes” overlay is meant to provide an understanding of which classes
this author has published in. We create an overlay over the classes this author
published under. Classes with a high value are encoded yellow and red thosewith a low value interpolating everything in between.
The “Timeline” overlay seeks to offer a timeline for the author’s work. This issimilar to the first use case where we try to display the progress of the classes overtime. This case is simpler since most authors do not have many publications. In
this case the average does offer a meaningful intuition of the authors publication
behavior. Commonly there also are no outliers because authors publish during
their active careers which is a short window of time.
When searching results appear all over the map. Our user is only interested
in her top MSC classes and hence would like to filter the results (4.4). Since
there are potentially a lot of results a solution that lets the user pick markers
individually is not viable. We also want to take advantage of the fact that similarclasses are geographically near in the map. After obtaining the results a tool canbe offered. This tool will let the user draw on top of the map. This will generate
a layer with geometrical objects that encapsulate the desired results. After a

Fig. 3: General layout.

subset of the results has been selected they can confirm their selection and only
the selected ones would remain on the map. This is done by going through all
the markers and checking if they are inside one of the drawn polygons. Since
the map can only display a limited amount of information we offer a link to theZentralblatt site with information about all the individual results. This link is
updated throughout the filtering process to refer only to the relevant markers.

(a) Markers.

(b) Marker expansion.

Fig. 4: Marker overview.

(c) Marker popup.

6

User Interface

In order to have all of these features we need an interface for the user to interact
with the map. There are several components that need to be created to support
all of the use cases. They are afterwards integrated to provide all of the desiredinteraction.
The map is displayed by the Leaflet service which provides zooming frompreviously generated tile images of the map.
A search bar has been placed on the top left corner of the actual map area
(Fig. 3). This integrates it and informs the user that the search results will bein the scope of the map. A mode is selected by placing a shortcut followed by a“:” in front of the query. For example “a: Carmela Acevedo” will search for an
author named “Carmela Acevedo”.
The results are displayed as markers on the map (Fig. 4a). Clicking on overlapping markers displays all of them in a circle. In this way markers can maintaintheir position while the user has the ability to navigate them all (Fig. 4b). All
markers have a popup containing the title of the respective object and a link to
Zentralblatt with the specific results data (Fig. 4c).

(a) Class timeline with legend(b) Legend for specific class on hover.

Fig. 5: Timeline.

(a) Author popup.

(b) Author classes.

Fig. 6: Author information.

For the current areas of mathematics use case (4.2) we provide abutton “Class timeline” which generates the country overlay (Fig. 3). Below the search there is a HTML div
containing a legend for the overlay(Fig. 5a). Whenever a user hovers overa country it is updated to contain specific information about the respective
country. This helps to better understand the colors and provides exact
information to the user (Fig. 5b).
To provide more information about
Fig. 7: Filtering toolbar.
the author (4.3) we use overlays thatcan be visualized by clicking one of
the two buttons in their marker popup. Each button prompts the appearance of

(a) Map with results.

(b) Drawn circle.

(c) Filtered markers.

Fig. 8: Filter workflow.

a respective overlay. This is done in the exact same way as in the general casealso with a legend for extra information (Fig. 6).
When a search that requires filtering (4.4) is performed we add an extra
toolbar to the map below the information area. It contains four buttons: draw,
edit, remove and confirm (Fig. 7). These buttons contain hover states to guidethe user. After obtaining results users can draw circles around markers they
desire to keep. By confirming they obtain only the selected results (Fig. 8).

7

Evaluation

In order to determine if this system is a successful aid for searching an evaluation
was performed. This process sought to compare the present solution to previously
existing systems.
7.1

Methods

The system was evaluated five mathematically inclined university students inthe process of obtaining either an undergraduate or graduate degree. After agiven time to get familiar with the system they were asked to perform threetasks both in the map and the Zentralblatt search portal. The tasks were:
1. Find the most currently active class.
2. Find a specific author and describe their publishing behavior.
3. Search for a formula and obtain results in one specific class.
They finally filled out a survey comparing the ease for obtaining informationin both systems.

7.2

Results

All the participants grasped the concept of the map during the beginning of
the evaluation and worked diligently through the tasks [Ace14]. They found themap to be a useful metaphor to display the information with. After having theresults and data available on the map they were able to successfully analyze it
and understand how results were related to each other.
Participants considered that the overlays providing extra information werevery useful. Filtering results was rated to be easier on the map than on the
Zentralblatt search. Users did have technical problems with specific tools andbuttons that hindered at moments their possibility of obtaining results.
7.3

Discussion

There were some technical problems related to the implementation of the system.
Users could not easily find buttons which was related to the fact that they wereoutside of their field of vision (the map) and too small. The filtering tool seemed
too complicated because it demanded too many steps.
We can consider that the use of the map to display the information was
successful. Users were able to understand it and moreover they were able todraw conclusions from it. Objects that were displayed in the map were quickly
interpreted by the participants. This shows us how useful the map can be inhierarchical search scenarios where results have a semantical relation.

8

Conclusions and Future WorkIn this project we have investigated the potential of maps as search tools forlarge hierarchical information databases. For this we developed a framework thatenables users to interactively perform three search tasks: obtain general information about the current developments in mathematical publications, find fields
of interest of particular authors and filter results according to their semantical
relations. We have evaluated this framework on five users and concluded that
our tool is more helpful to answer these questions than typical search engines.
Therefore we prove that maps are a useful search tool because they provide an
overview of a topic while letting users investigate areas without losing track of
the big picture. The best tools to facilitate hierarchical interactive search are yet
to be found.
To improve the map and provide more interaction possibilities, queries shouldbe able to be combined and compared in order to provide more specific results.
We are currently not fully taking advantage of the hierarchical nature of the map.
A new map could be generated that displays further levels and even individual
objects. The map could also be integrated with previous search systems, suchas the Zentralblatt search, to complement each other. Finally, new maps should
be used with the existing framework in order to evaluate whether the results are
related to the map or the interactive framework component.

Acknowledgements Work on the concepts presented here has been partially supported by the Leibniz association under grant SAW-2012-FIZ KA-2. We areindebted to Wolfram Sperber from ZBMath for support with the data and to
Jan Wilken Dörrie and Andrea Kohlhase for insightful discussions.

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