birthdaymonth == {(Tod,Jan), (CD,Mar), (Nor,May), (Win,Jun), (Eth,Jun), (Jo,Jul), (Ann,Aug), (Kay,Sep), (Ma,Oct), (Ron,Oct), (AJ,Nov), (Da,Dec)}

Source - NAME

Target - MONTH

familybirthdaymonth = birthdaymonthÛ{Tod,CD,Win,Eth,Ann,Kay,Ma,Ron,Da}Ü

birthdaymonth ~ = {Jan šŽ Tod, Mar šŽ CD, May šŽ Nor, Jun šŽ Win, Jun šŽ Eth, Jul šŽ Jo, Aug šŽ Ann, Sep šŽ Kay, Oct šŽ Ron, Oct šŽ Ma, Nov šŽ AJ, Dec šŽ Da}

parentbirthdaymonth = {Ma,Da} ¨ birthdaymonth

nonfamilybirthdaymonth = {Tod,CD,Win,Eth,Ann,Kay,Ma,Ron,Da} ° birthdaymonth

summerbirthdaymonth = birthdaymonth © {Jan,Jul,Aug}

non30birthdaymonths = birthdaymonth ± {Sep,Apr,Jun,Nov}

bmonth_pcodes = postcode † birthdaymonth

pcodes_bmonth = birthdaymonth ‡ postcode