科技爱好者周刊（第 388 期）：测试是新的护城河

The basic problem in the cooperation theory is to justify the cooperation. Here we propose a new approach, where players are driven by their altruism to cooperate or not. The probability of cooperation depends also on the co-player's reputation. We find that players with positive altruism cooperate and met cooperation. In this approach, payoffs are not relevant. The mechanism is most efficient in the fully connected network.

We present a comprehensive study of the phase transitions in the single-field reaction-diffusion stochastic systems with field-dependent mobility of a power-low form and the internal fluctuations. Using variational principles and mean-field theory it was shown that the noise can sustain spatial patterns and leads to disordering phase transitions. We have shown that the phase transitions can be of critical or non-critical character.