What is the meaning of (a) or (b) after the patent number of each country?

I don't know what you want to ask is the meaning of the letters after the patent number. The specific meaning is as follows

For patents issued after July 1 2004:

Disclosure of application for invention patent

Announcement of invention patent authorization

Announcement that the patent right for invention is partially invalid

U utility model patent authorization announcement

Y announcement of partial invalidation of utility model patent right

Announcement on authorization of patent for design or announcement on invalidation of part of patent right

For patents issued before July 1 2004:

Disclosure of application for invention patent

Announcement of invention patent authorization

Y utility model patent authorization announcement

Design patent licensing company