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.

基于增加财政收入、发挥房产税对住房市场的调控及对居民收入分配的调节作用，我国在上海和重庆开展房产税试点改革，尝试将个人住房纳入了房产税征税范围，但截止目前仍难以扩围。本文分析了试点改革的效果与存在的问题，并提出了相应的政策建议。