Banned math book
In Argentina a military governor from our last dictatorship banned teaching Set theory because it was a "collectivist idea" and was "against the individual". You can learn more here (spanish): https://www.nexos.com.mx/?p=3404Specifically, they banned the book "Conceptos básicos de matemática moderna" (Modern Maths Basic Concepts) / Hernández-Rojo-Rabuffetti