ey l ▁transform : ▁two ▁G aus si ans ▁compose ▁with ▁this ▁ ★ - product ▁according ▁to ▁a ▁hyper bol ic ▁tang ent ▁law : ▁▁▁ ▁( Note ▁the ▁classical ▁limit , ▁. ) ▁ ▁Every ▁correspond ence ▁pres cription ▁between ▁phase ▁space ▁and ▁Hil bert ▁space , ▁however , ▁indu ces ▁its ▁own ▁proper ▁ ★ - product . ▁ ▁Similar ▁results ▁are ▁seen ▁in ▁the ▁Seg al – B arg mann ▁space ▁and ▁in ▁the ▁the ta ▁representation ▁of ▁the ▁He isen berg ▁group , ▁where ▁the ▁creation ▁and ▁anni h ilation ▁operators ▁ ▁and ▁ ▁are ▁understood ▁to ▁act ▁on ▁the ▁complex ▁plane ▁( res pect ively , ▁the ▁upper ▁half - plane ▁for ▁the ▁He isen berg ▁group ), ▁so ▁that ▁the ▁position ▁and ▁moment a ▁operators ▁are ▁given ▁by ▁ ▁and ▁. ▁ ▁This ▁situation ▁is ▁clearly ▁different ▁from ▁the ▁case ▁where ▁the ▁positions ▁are ▁taken ▁to ▁be ▁real - valu ed , ▁but ▁does ▁offer ▁ins ights ▁into ▁the ▁overall ▁algebraic ▁structure ▁of ▁the ▁He isen berg ▁algebra ▁and ▁its ▁en velope , ▁the ▁W ey l ▁algebra . ▁ ▁References ▁ ▁Category : Math emat ical ▁quant ization ▁Category : Math emat ical ▁physics <0x0A> </s> ▁The ▁tang elo ▁( ▁, ▁ ▁; ▁C . ▁ret icul ata ▁× ▁C . ▁maxim a ▁or ▁× ▁C . ▁parad isi ), ▁Cit rus ▁× ▁tang elo , ▁ ▁is ▁a ▁cit rus ▁fruit ▁hy brid ▁of ▁a ▁Cit rus ▁ret icul ata ▁variety ▁such ▁as ▁mand