2 ancestry: of commits, a partial order
3 C > D C is a descendant of D
4 inclusion: commit includes change made in another
5 a partial order, consistent with ancestry but more partial
10 patch P is two subset of commits, Ptip and Pbase
11 each subset has a single ur-ancestor C0_Ptip resp C0_Pbase
12 these subsets mutually exclusive
13 P(C) is either Ptip, Pbase, or nil (recorded in commit)
15 commits fall into three categories wrt P
18 \forall D \elem Ptip, C ] D <=> C > D
21 \forall D \elem Ptip, !(C ] D)
28 the ends E(C,Px) of Px = Pbase or Ptip are
29 every maximal Ce < C in Px ie
31 C > Ce ^ !\exists C s.t. C > Ce
44 Cx [ C <=> Cx = D v Cx [ D
48 make C from D, P, A-, A+