preliminary SOLUTIONS

The teams should send their preliminary solutions to before November 1 at 22:00 (Paris).

Note that after sending the preliminary solutions, the teams may continue working on the problems and make modifications until sending their final solutions.  

Files with extension PDF are accepted. There should be a separate file per problem, named as  


Limits per file: 5 MB, 30 pages (A4, 11pt). 

The pages should be numbered.

The preliminary solutions will be checked by experts, and the teams will be ranked according to the quality of their solutions (the team with the best materials will have rank 1). 

The division into Groups for Round 1 will be made by the following rule. For example, if there are 15 teams ranked from 1 to 15, then the groups will be


The teams should send their final solutions to before November 14 at 22:00 (Paris)

It is not required to send solutions on all the problems. However, at least six problems should be investigated.

Files with extension PDF are accepted. There should be a separate file per problem, named as 


Limits per file: 5 MB, 30 pages (A4, 11pt). 

The pages should be numbered.

These and only these papers will be discussed during the tournament and no text editing will be permitted. An exception is in the case of correcting minor errors, which should be mentioned during the presentation. During his/her performance the reporter is only allowed to present:  

parts of the paper with no modification, that is, exact statements with their original numberings, figures and diagrams; 

sketches of solutions and proofs, and ideas used in the paper. 

The first page of each file should contain the number and the name of the problem, the name of the team, the authors and an abstract (a brief summary of results and methods, about half to ⅔ of the page). A model for the first page:

Problem 4:  A Baby Chess

Team: France 2 

Authors: Ivan Ivanov, John Johnson


In this paper we classify the winning strategies for the first player in the case...

All paper and electronic sources (books, articles, etc.) directly involved in the proofs should be mentioned in the end of the papers. For instance, if a team uses an already known and non-obvious result, the result should be stated explicitly and a reference should be provided with citations where it is involved in the solution.


The first draws will be held online on November 15 at 17:00 (Paris):

Belarus  18:00

Bulgaria  18:00

France  17:00

Georgia  19:00

Germany  17:00

India  20:30

Pakistan  20:00

Poland  17:00

Romania  18:00

Russia  18:00

Thailand  22:00

The teams will have to join an online conference room, the link to which will be given beforehand.

During the first draws, each team may reject up to 6 different problems without penalty (the rejections of the first draw will be forgotten during the second draw).

Choose your tactic: either you want to present your best problems in the rounds to get to the finals, or you are sure to succeed in the rounds anyway and you keep your best problem for the finals.

According to the regulations

The teams are divided into groups based on their preliminary solutions.  

A separate draw will decide the order within each group. After that, the following action will be performed several times:

Step. An organiser places P cards with numbers from 1 to P in a row, where P is the number of problems. A captain picks an integer n from 1 to P. The organiser suggests the problem numbered by the integer written on the n-th card.  

If the captain accepts the problem, then the card is taken away.  

If the captain refuses a problem which he/she has already refused in the same draw, then the captain has to choose another card.  

If the captain refuses a new problem, then the card is turned back over and all cards are shuffled.

The step is repeated for the next captain within the group and so on.