>>55812452>>55814361>>55815930It's complicated because むげん mugen could mean
>夢幻 dream, fantasy, vision>無現 eternity, infinity, everlasting>無限 limitless, boundless, endlessAnd the only use of kanji for this in the series is this Miku's song
>遠い夢じゃない 幻でもない It's not a distant dream nor a mirage>ミストボール 輝く The Mist Ball shines in radiance>ぼくの歌と きみの声で With my song and your voice>こころのしずく満たしていく Filling up the Soul Dew>無限の空 めがけてラスターパージ Luster Purge aimed towards the endless skies>あの日の きみに贈る To you on that day>むげんのチケット Eon TicketWhile the lyrics don't forget to reference the fantasy nature of the duo (夢), mugen (無限) is used in the "devoid of restrictions" sense here. Still, it's tecnically just part of the lyrics and when Miku signs the name of the pokemon's category (via the ticket's name) she still says mugen as むげん
tl;dr
It's complicated, but it seems like it's mugen as in infinite, but with heavy fantastic connotations
