Lemma 102 in the compatible-family form: indifference to empty boundary members #
The value of BD_{n,m,j} on a relatively compact open does not see empty members of the boundary
(BDanFam_indifferentToEmptyMembers; the counterpart of BDan_indifferentToEmptyMembers of
BDIndiff.lean; for boundary members the counterpart of Kollár's convention that empty
blow-ups are ignored, [Kol07, 32]): when F' is E with empty members deleted along an order
embedding e,
the value at the member e i of E equals the value at the member i of F', on every open. As
in BDIndiff.lean, the core on an open is first written over an arbitrary centre and transform
(coreFamOn_eq_of_eq, the counterpart of core_eq_of_eq; the centre and the transform at e i and
at i agree as sets by Zminus1_eq_of_hyp_eq and transformS_eq_transformSOf, so both sides live
on the same data), and then the input family's own indifference identifies the two values read at
the trace of π_{-1}^{-1}(U): the restricted boundary of E - E^{e i} embeds that of F' - F'^i
along e, with empty members outside the range.
coreFamOn_eq_of_eq— the core on an open over an arbitrary closed hypersurfaceZand a closed hypersurfaceS'of its blowing-up (withpiOpenOf,liftInclOfofBDFam.lean);coreFamOn_indifferentToEmptyMembers,BDanFam_indifferentToEmptyMembers.
This is the indifferentToEmptyMembers field of Lemma 102's family data bdanFamDataOfInput in
BOanFamOfInput.lean.
The core on an open over an arbitrary centre and transform #
The core on an open (coreFamOn, BDFam.lean) read over any closed hypersurface Z = Z_{-1}
and any closed hypersurface S' = S_0 of its blowing-up (a substitution; the counterpart of
core_eq_of_eq in BDOf.lean).
Indifference #
The core on an open is indifferent to empty boundary members: the core at the
member e i of E is the core at the member i of F', when F' is E with the empty members
outside the range of e deleted. The first centre and the transform are the same sets, and the
input family is indifferent, on the trace of π_{-1}^{-1}(U), to the empty members of the
restricted
boundary (E - E^{e i})|_{S_0}, which embeds (F' - F'^i)|_{S_0} along e.
The value of BD_{n,m,·} on every relatively compact open is indifferent to empty boundary
members: when F' is E with the empty members outside the range of the order
embedding e deleted, the value at the member e i of E equals the value at the member i of
F'. This is coreFamOn_indifferentToEmptyMembers at the tuned triple (the tuning keeps the
boundary).