from research import *
s=begin(488,'Cainan as a cross-mode vector','Which shared structures survive the admitted 130/460 insertion?',{'delta_R':130,'delta_C':460,'MT_bridge':9890},['Strategy §§3.2,4.4','File18 Cainan controls'])
bridge=9890+460-130
finish(s,{'bridge_change':330,'weighted_point_change':F(4*460+130,5),'restored_bridge':bridge,'Sothic_factor':F(bridge,1460),'finite_state_rule':'OFF -> ON once where admitted; native LXX starts ON'},
 'One inserted row accounts for both130 and460, increases the cumulative–regular bridge by330, and sends9890 to10220=7×1460. It shifts the weighted point by394, so it is not a12026-preserving operation.',
 'Check whether the rounded regular reversal construction survives native LXX inputs.',{'bridge':bridge==10220==7*1460,'weighted_shift':F(1970,5)==394})