:PROPERTIES: :ID: fdcecb13-35e1-439c-ba13-5c63bd7342c3 :ROAM_ALIASES: continuous mapping "continuous function" :END: #+title: Mapping #+author: Preston Pan #+description: mapping the thought landscape out. #+options: broken-links:t * Introduction A /mapping/, or /continuous function/ in a [[id:b0784577-9691-4c8e-a8e4-974a7c9c4949][topological space]] is defined as a [[id:b1f9aa55-5f1e-4865-8118-43e5e5dc7752][function]] $f$ such that the preimage of an [[id:b0784577-9691-4c8e-a8e4-974a7c9c4949][open set]] is open, or $f^{-1}(U)$ is open for all [[id:b0784577-9691-4c8e-a8e4-974a7c9c4949][open sets]] $U$.