Notation T := (Tread, Tfull).

Axiom protocol_piece_share_join : forall sh1 sh2 sh l s1 s2 (Hsh : sepalg.join sh1 sh2 sh)
(Hsh1 : sh1 <> Share.bot) (Hsh2 : sh2 <> Share.bot),
protocol_piece sh1 l s1 ord T * protocol_piece sh2 l s2 ord T =
!!(s1 = s2) && protocol_piece sh l s1 ord T.