:: deftheorem Def14 defines - CGAMES_1:def 14 :
for g being ConwayGame
for b₂ being set holds
( b₂ = - g iff ex f being Function st
( dom f = the_Tree_of g & b₂ = f . g & ( for g1 being ConwayGame st g1 in dom f holds
f . g1 = left-right(# { (f . gR) where gR is Element of the_RightOptions_of g1 : the_RightOptions_of g1 <> {} } , { (f . gL) where gL is Element of the_LeftOptions_of g1 : the_LeftOptions_of g1 <> {} } #) ) ) );