These equations are on gates to the John Dalton building in Manchester UK: $$X \geq Y \text{ iff } \not\exists \, x_r \leq Y \text{ & } X \leq Y_L $$ $$X = Y \text{ iff } X \leq Y \text{ & } Y \geq X$$ Here’s a picture of the gates

Does anybody know what they mean or which work they relate to? I've tagged this mathematical physics, but am not really sure if this is correct.