发表机构
Global Education Center, Waseda University（早稻田大学全球教育中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究分析日本2020年旅游冲击期间奢侈品转售网络的共同购买变化，发现买家减少27%和交易额下降35%，但网络检验结果不确定且对构建方式敏感，需重建图表零模型和检测下限。
AI 中文摘要
日本2020年的旅游冲击与一家二手奢侈品转售中介的买家数量减少27%和总商品交易额下降35%同时发生。我们比较了2019年和2020年记录的品牌标签的共同购买预测，使用了五种标签不变指标的Holm校正组合以及Portrait Divergence，并针对两个重建两张图表的排列零模型进行检验。两种检验均未区分整个年份（最小Holm p值为0.407；在设计匹配的配对交换零模型下为0.097）。对于品牌的一次随机两区块分割，该检验组合在83次（共100次模拟）中检测到了30%多品牌购物篮（10,399个第二组购物篮中的178个，占1.7%）的定向转移（在11次分割中，83-92次（共100次）均至少为80）；Portrait Divergence仅在完全转移时达到80%的统计功效。观察到的平均度和聚类系数的下降类似于20-30%转移的情况，但未出现定向转移所导致的度同配性上升。仅基于构成变化的模型对观察到的流失进行检测，在100次模拟中仅有15次被检测到。结果随构建方式而变化：在去除残差和材料标签后（事后分析），平均度在配对交换零模型下区分了年份（Holm p = 0.030），并且Portrait Divergence在最宽的构建方式下以及4月至12月期间，未经调整即降至0.05以下。冲击期间的网络比较需要重建图表的零模型以及每个指标的检测下限。
英文摘要
Japan's 2020 tourism shock coincided with 27% fewer buyers and 35% lower gross merchandise value at one second-hand luxury resale intermediary. We compared 2019 and 2020 co-purchase projections of recorded brand labels with a Holm-corrected battery of five label-invariant metrics and Portrait Divergence against two permutation nulls rebuilding both graphs. Neither test separated the full years (smallest Holm p 0.407; 0.097 under the design-matched paired-swap null). For one random two-block split of brands, the battery detected a planted redirection of 30% of multi-brand baskets (178 of 10,399 second-group baskets, 1.7%) in 83 of 100 simulations (83-92 of 100 across 11 splits, all at least 80); Portrait Divergence reached 80% power only at full redirection. Observed falls in mean degree and clustering resembled those of 20-30% redirection, but the planted rise in degree assortativity was absent. A composition-only model of the observed attrition would be detected in only 15 of 100 simulations. Results moved with construction: without residual and material labels (post hoc), mean degree separated the years under the paired-swap null (Holm p = 0.030), and Portrait Divergence fell below 0.05, unadjusted, at the widest construction and within April-December. Shock-period network comparisons need rebuilt-graph nulls and a per-metric detection floor.
Comments79 pages (36 main text, 43 supplementary information), 5 figures, 2 tables. Code: https://doi.org/10.5281/zenodo.21194626
