Want to take part in these discussions? Sign in if you have an account, or apply for one below
Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.
Just for completeness, to go with e-invariant and f-invariant.
We don’t yet have a page for f-invariant.
spelled out (here) the example of how the d-invariant specializes to the ordinary Hopf degree.
Am adding this example now also to degree of a continuous function and to Hopf degree theorem
I have added a section “Trivializations of the d-invariant” (here) with some observations.
While from a modern abstract homotopy-theoretic perspective this is really a one-line observation, unwinding this accounts for (and completes) a fair bit of argument in Section 16 of Conner-Floyd’s 66 book (for which no modernized account seems to exist?!), and it also sets the pattern for the other classical constructions of the e-invariant and the Hopf invariant.
So therefore I thought it would be useful to spell this out a little. Also, this section provides details now linked to at MUFr and at Adams e-invariant – Construction via unit cofiber cohomology theories.
Some new candidates for a HoTT treatment?
I had had that same thought, yes. The style of construction that I am writing out at Adams e-invariant – Construction via cofiber theories should lends itself to full formalization in HoTT. For instance the Conner-Floyd theorem becomes a formal corollary by factoring a homotopy pasting diagram (here) .
1 to 7 of 7