The power pairing #
For a Mod-internal duality datum on a pair of modules, the nested
pairing of equal tensor powers: peel the innermost pair — the last
factor of the M'-power against the first factor of the
M-power — evaluate the datum, braid the scalar out, and multiply
onto the pairing of the remaining powers. The pairing is defined
at the raw tensor-power level by recursion on the arity; the
descent obligations through the module-power and module-tensor
coequalizers reduce, by the same recursion, to the datum's
linearity and the commutativity of the monoid.
The datum's pairing at the raw tensor level #
The datum's pairing evaluated on the raw tensor product.
Equations
- RS.pairRaw A M M' d = CategoryTheory.CategoryStruct.comp (RS.modTensorπ A M' M) d.pair
Instances For
Raw linearity of the pairing in the M'-factor: acting on the
first factor multiplies the scalar.
Raw linearity of the pairing in the M'-factor: acting on the
first factor multiplies the scalar.
The middle slide across the raw pairing: the braided right
action on M' and the left action on M pair equally.
The middle slide across the raw pairing: the braided right
action on M' and the left action on M pair equally.
Raw linearity through the braided right action: acting on the
right of the M'-factor braids the scalar out to the left and
multiplies.
Raw linearity through the braided right action: acting on the
right of the M'-factor braids the scalar out to the left and
multiplies.
Raw linearity in the M-factor: acting on the left of the
M-factor braids the scalar out to the left and multiplies.
Raw linearity in the M-factor: acting on the left of the
M-factor braids the scalar out to the left and multiplies.
The nested power pairing #
The nested power pairing at the raw tensor level, by
recursion on the arity: at n + 1, peel the first factor of the
M-power, pair it with the exposed last factor of the M'-power,
braid the resulting scalar past the remaining M-power, and
multiply it onto the pairing of the remaining powers.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The base case of the power pairing.
The recursion of the power pairing.
The generic pairing step #
The recursion step of the power pairing, over an arbitrary
continuation pairing: pair the exposed last M'-factor against
the exposed head M-factor, braid the scalar past the remaining
block, and fold it onto the continuation by multiplication. All
extraction and naturality laws are proved at this generality, so
that the inductions over the arity reduce to threading through
the step.
The generic recursion step of the power pairing.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The recursion of the power pairing through the generic step.
Naturality of the step in the block variable.
Naturality of the step in the continuation variable.
Scalar extraction over a symmetric base #
The descent obligations move an acted scalar across whole tensor blocks in both directions; the two routes agree only when the braiding is symmetric. The pairing calculus therefore runs over a symmetric base from here on — which is the generality of the Key Lemma itself. The section is fresh, so that the symmetric structure's braiding is the only braiding in scope.
Concatenation against the head peel: concatenating onto a power with an exposed head factor and peeling the head of the result equals peeling the first block and concatenating the rest under the exposed factor.
A strand crossing out to the left through an evaluated pairing may instead cross to the right and braid past the output.
Scalar extraction at the pair: acting on the right of the
M'-factor equals sliding the scalar rightwards past the
M-factor, pairing, and multiplying from the right.
Scalar extraction at the pair: acting on the right of the
M'-factor equals sliding the scalar rightwards past the
M-factor, pairing, and multiplying from the right.
Scalar extraction at the pair, second slot: acting on the
left of the M-factor equals sliding the scalar rightwards past
the M-factor, pairing, and multiplying from the right.
Scalar extraction at the pair, second slot: acting on the
left of the M-factor equals sliding the scalar rightwards past
the M-factor, pairing, and multiplying from the right.
Scalar extraction at the pair, second slot from the
right: acting through the braided right action on the
M-factor multiplies the pairing from the right, with no
crossing at all.
Scalar extraction at the pair, second slot from the
right: acting through the braided right action on the
M-factor multiplies the pairing from the right, with no
crossing at all.
Scalar extraction at the last M'-factor: acting on the
right of the exposed last factor of the M'-power equals braiding
the scalar past the whole M-power and multiplying the pairing
from the right.
Generic scalar extraction at the M'-slot of the step:
acting through the braided right action on the exposed M'-factor
equals braiding the scalar past the peeled block and multiplying
the step from the right.
Generic scalar extraction at the M-slot of the step:
acting on the exposed head M-factor equals braiding the scalar
past the peeled block and multiplying the step from the right.
Over a symmetric base the left action is the braided right action after one crossing.
Generic scalar extraction at the M'-slot, for a scalar
arriving from the left of the consumed factor.
The top-slot slide law: for a continuation pairing that absorbs the braided right action on its last block factor — the extraction property of the power pairing — the two legs of the top slot window agree after the generic step.
Transport of the power pairing along an arity equality.
The head-slot slide law: the two legs of a slot window on
the first two M-factors agree after the doubled generic step.
The statement is closed — the continuation is arbitrary.
The top slot relation of the power pairing: at the slot
touching the last two factors of the M'-power, the two legs
pair equally.
The first slot relations of the power pairing: at every
slot of the M'-power, the two legs pair equally.
The second slot relations of the power pairing: at every
slot of the M-power, the two legs pair equally.
Extraction propagates through the step: the step over an extracted continuation is the extraction of the step, with the scalar crossing the continuation block.
Scalar extraction at the tail of the M-power: the tail
action on the M-power extracts as the scalar braiding past the
whole power and multiplying the pairing from the right.
The descended pairing #
The two-stage descent of the raw pairing through the module-power
coequalizers, mirroring the descent of the raw multiplication:
the slot relations assemble over the biproduct legs, the first
stage descends the M'-power against the ambient M-power, and
the second stage descends the M-power.
The first slot relations, in cast-carrying form.
The first stage of the pairing descent: the raw pairing
descends through the M'-power against the ambient
M-power.
Equations
- RS.pairPowStage A M M' d n = RS.modPowWhiskerRightDesc A M'.X n (RS.tensorPow D M.X n) (RS.rawPair A M M' d n) ⋯
Instances For
Defining equation of the first stage.
Defining equation of the first stage.
The first stage coequalizes the left-whiskered legs of the
M-power.
The descended power pairing on the module powers, in two stages.
Equations
- RS.pairPow A M M' d n = RS.modPowWhiskerLeftDesc A M.X (RS.modPow A M'.X n) n (RS.pairPowStage A M M' d n) ⋯
Instances For
Defining equation of the descended pairing.
Defining equation of the descended pairing.
The middle relation: the descended pairing coequalizes the module-tensor legs of the power bundles.
The Mod-internal power pairing: the descended pairing on the module tensor product of the power bundles.
Equations
- RS.modPowPairing A M M' d n = RS.modTensorDesc A (RS.modPowMod A M'.X n) (RS.modPowMod A M.X n) (RS.pairPow A M M' d (n + 1)) ⋯
Instances For
Defining equation of the Mod-internal power pairing.
Defining equation of the Mod-internal power pairing.
The section of the symmetric power, as a morphism of modules.
Equations
- RS.symPowσMod A n = { hom := RS.symPowσ A X (n + 1), isModHom := ⋯ }
Instances For
The symmetric power pairing: the Mod-internal pairing on the symmetric powers, through the sections.
Equations
- RS.symPowPairing A M M' d n = CategoryTheory.CategoryStruct.comp (RS.modTensorMap A (RS.symPowσMod A n) (RS.symPowσMod A n)) (RS.modPowPairing A M M' d n)
Instances For
Defining equation of the symmetric power pairing.
Defining equation of the symmetric power pairing.