Hessenberg relies on inv but is defined for RingElement

Nemocas / AbstractAlgebra.jl

Generic abstract algebra functionality in pure Julia (no C dependencies)

https://nemocas.github.io/AbstractAlgebra.jl/dev/index.html

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Hessenberg relies on inv but is defined for RingElement #630

Closed wbhart closed 4 years ago

wbhart commented 4 years ago

If hessenberg is called on a matrix over ZZ it calls inv(::BigInt) (or inv(::fmpz) in Nemo. However it is defined incorrectly by Julia for BigInt and not defined at all for fmpz in Nemo.

It's not clear we actually want to define inv for ZZ or not. We've been using div to separate fields from other kinds of rings.

One possibility would be to use divexact instead in hessenberg.

wbhart commented 4 years ago

See #155

wbhart commented 4 years ago

We decided to define inv for all rings as inv(n) = divexact(1, n)