theorem Th26: :: MIDSP_2:27

for M being non empty MidStr holds
( M is MidSp iff ex G being non empty right_complementable Abelian add-associative right_zeroed midpoint_operator addLoopStr ex w being Function of [: the carrier of M, the carrier of M:], the carrier of G st
( w is_atlas_of the carrier of M,G & w is associating ) )