from research import *
s=begin(497,'One shared tail links12026 and14726','How does the documented1400 leg connect the two backbone anchors?',{'Conquest':1406,'Nativity':6,'primary_reversed_sum':10620},['File52c §§3.3–3.4'])
tail=1406-6;gain=inv(tail)-tail;old=1406+10620;new=6+inv(tail)+10620
finish(s,{'tail':tail,'reversed_tail':inv(tail),'net_anchor_change':gain,'Conquest_backbone':old,'Nativity_backbone':new,'Nativity_span':new-6,'E_span':E*(new-6)},
 'Appending the shared1400 leg changes the reconstructed endpoint by4100−1400=2700. Both primary paths therefore continue together from12026 to14726. The backbone’s14720 span then expands to16000.',
 'Identify the decimal gain law that explains the990 and2700 increments.',{'continuation':new==old+gain==14726,'expansion':E*(new-6)==16000})