What is non-hückel double bond of Aromaticity? [duplicate]

Chemistry of Aromaticity. What's non hückel double bond ? What are the difference between hückel and non-hückel double bond ? [ Here, in figure the green one is non hückel double bond ]

• There is no intrinsic difference. Hückel's rule counts the number of pi electrons in a closed ring. It says nothing about other double bonds. – Karl Jul 14 '19 at 23:26

In the given molecule Pyrene , the π bond shown in green is in cross conjugation (shown in green in figure 1). This bond( figure 2) is excluded from interaction with rest of conjugated system. Hence , the central $$\ce{C=C}$$ isn't hosted by the largest p orbital loop, so it's not counted towards Hückel's rule for aromaticity.
The outer periphery (shown in blue in figure 3), is a loop of $$\ce{14 π}$$ electrons , therefore aromatic. This may be possible hückel double bond you are referring to.