>>3700238 (lb)
THEORY
https://en.wikipedia.org/wiki/Phi
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From https://answers.yahoo.com/question/index?qid=20110826174406AAJRsvK&guccounter=1 (ikr)
The circle with a line going vertically through it is the Greek letter phi. In set theory, it represents the empty set (the set that.contains no elements) In algebra, it represents "no solution."
no solution