The order reduction read at the nonmonomial triple #
"Apply order reduction (68) to N(I)" [Kol07, 111, Step 1]: a round of the rounds on the
nonmonomial part reads the order reduction BO_{n,d} at the nonmonomial triple (M, N(๐), E).
Packaged as a family functor in its own right, nonmonomialFunctor bo on the class
NonmonomialClass d of triples whose nonmonomial triple lies in the domain of BO_{n,d}, it
inherits the two naturality properties from bo:
- it commutes with local analytic isomorphisms (the analogue of [Kol07, Theorem 103 (2)]),
because the nonmonomial part commutes with pull-back (
NonmonomialComap); - it is indifferent to empty boundary members (the counterpart, for boundary members, of
[Kol07, 32]), because the
nonmonomial part is (
nonmonomialTriple_eq_of_isEmptyExtension).
The value of the round in StepALink.lean is the value of this functor at the induced triple
(BState.roundValue_eq_nonmonomialFunctor, a rfl), so the transport lemmas for values at induced
triples (InducedValueFunctor.lean) apply to the link of the descent.
The class of triples whose nonmonomial triple lies in the domain of BO_{n,d} (1 โค d,
ord N(๐) โค d everywhere, finitely many nonempty members): the domain of the round on the
nonmonomial part [Kol07, 111, Step 1].
Equations
Instances For
The order reduction read at the nonmonomial triple, as a family functor on
NonmonomialClass d [Kol07, 111, Step 1]: the value of bo at (M, N(๐), E), re-typed as a family
for (M, ๐, E) (CompatibleFamily.changeTriple; the triple is not part of the data of a compatible
family).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The class is closed under pull-back along local analytic isomorphisms (NonmonomialComap and
boClass_of_isPullbackOf).
The class is indifferent to empty boundary members: deleting or adding empty members keeps the
nonmonomial triple's ideal (nonmonomialTriple_eq_of_isEmptyExtension) and the finiteness of the
nonempty members.
The converse: a triple whose boundary is an empty extension of the boundary of a triple of the class (same ideal) lies in the class.
The family read at the nonmonomial triple commutes with local analytic isomorphisms
(the analogue of [Kol07, Theorem 103 (2)] for the composite), since the nonmonomial triple of a
pull-back is the
pull-back of the nonmonomial triple (NonmonomialComap).
The indifference property with the boundary of the triple named by an equation (substituted),
the shape in which the property applies at nonmonomialTriple T, whose boundary is T.F only up to
the projection lemma nonmonomialTriple_F.
The family read at the nonmonomial triple is indifferent to empty boundary members (the
counterpart, for boundary members, of [Kol07, 32]): the nonmonomial triple of the triple with the
replaced boundary is the
nonmonomial triple with the boundary replaced (nonmonomialTriple_eq_of_isEmptyExtension), and bo
is indifferent.
The round's value #
The invariant of the descent puts the induced triple in NonmonomialClass d.
The value of the round is the value of the functor read at the nonmonomial triple, at the induced triple.