🧩⊂🖼️

#topology #topological space #subset #open set #part of a whole

🇽　　{⭕️}

#topology #open set #topological structure #mathematics #set theory #definition #tau #point-set topology

🧱➡️(🔓∩🔒)➡️🧩

#constructible set #algebraic geometry #locally closed set #open set #closed set #set intersection