Евгений Лакштанов

Евгений Лакштанов (Университет Авейру) посетил Лабораторию алгебраической геометрии в августе 2012 г.

На еженедельном семинаре Лаборатории он выступил с докладом "Продолжительность карточной игры в "Пьяницу".

Abstract: The game of war is one of the most popular international children's card games. In the beginning of the game, the pack is split into two parts, then on each move the players reveal their top cards. The player having the highest card collects both and returns them to the bottom of his hand. The player left with no cards loses. It is often wrongly assumed that this game is deterministic and the result is set once the cards have been dealt.However, it is not quite so; as the rules of the game do not prescribe the order in which the winning player will put his take to the bottom of his hand: own card, then rival's or vice versa: rival's card, then own. We provide an example of a cycling game with fixed rules. Assume now that each player can seldom but regularly change the returning order. We have managed to prove that in this case the mathematical expectation of the length of the game is finite. In principle it is equivalent to the graph of the game, which has got edges corresponding to all acceptable transitions, having got the following property: from each initial configuration there is at least one path to the end of the game.