What is the Greatest Name mentioned in the Obligatory Prayer?

Aug 2010
New Zealand mainly
It seems to be generally understood as "allah'u'abha", since the Aqdas also specifies:

It hath been ordained that every believer in God,
the Lord of Judgement, shall, each day, having washed
his hands and then his face, seat himself and, turning
unto God, repeat "Allah-u-Abha" ninety-five times."

and a letter on behalf of the House of Justice says (Sept 1, 1983):

"It would seem that there are in Norway many believers who draw particular benefit from meditation. The House of Justice suggests that for their private meditations they may wish to use the repetition of the Greatest Name, Allah-u-Abha, ninety-five times a day which, although not yet applied in the West, is among the Laws, Ordinances and Exhortations of the "Kitáb-i-Aqdas". (See p. 46 of the "Synopsis and Codification of the Kitáb-i-Aqdas".)

The synopsis and codification of the Aqdas also describes the 95 x Allah-u-abha as the 'greates name,' but I do not know whether that section of the codification came from Shoghi Effendi, or from the research department.

However Baha'u'llah, Ya-baha-u'l-abha, and allah'u'abha are all forms of the same name.