John Baez raises interesting points here that are somewhat peculiar to the 3rd & 4th dimensions given their relationship to the 4D quaternions. But there‘s a missed opportunity describing the symmetry in his way. It has to do with there being too many names for the 3D sphere S^3. https://twitter.com/johncarlosbaez/status/1290324611222011908
You can call S^3 by all of the following names:
S^3, Spin(3), SU(2), Sp(1)
only they lead to *different* generalizations.
Unfortunately
Spin(4)=SU(2)xSU(2) is seldom written Spin(4)=Sp(1)xS^3 which should be preferred. But why is one naming better? It‘s because it generalizes.
S^3, Spin(3), SU(2), Sp(1)
only they lead to *different* generalizations.
Unfortunately
Spin(4)=SU(2)xSU(2) is seldom written Spin(4)=Sp(1)xS^3 which should be preferred. But why is one naming better? It‘s because it generalizes.
The group Spin(8) is topologically also a product like Spin(4) of two spaces with algebraic product structures. Topologically, if we define Special Octonian groups so that Soct(1)=Spin(7), we have the following:
Spin(4)=Sp(1) x S^3
Spin(8)=Soct(1) x S^7
Raising a question.
Spin(4)=Sp(1) x S^3
Spin(8)=Soct(1) x S^7
Raising a question.
While S^7 isn’t a group, it‘s an H-space w/ a multiplication rule.
Q1: How does Spin(8)’s associative Lie Group multiplication Arise from a non trivial non-product rule from its two topological H-Space factors when only one of them is associative.
Q2: Has this been done?
Q1: How does Spin(8)’s associative Lie Group multiplication Arise from a non trivial non-product rule from its two topological H-Space factors when only one of them is associative.
Q2: Has this been done?

Also, I understand that some people elsewhere on Twitter have been struggling against the brutal tyranny of:
2 + 2 = 4
Good luck to you. You will need it.
2 + 2 = 4
Good luck to you. You will need it.