We need to define a * PFX b. Although we know that PFX a * b = PFX(a*b), we don't know that * is commutative (ie a * b = b *a ) so we cannot assume that PFX(a*b)=PFX(b*a) or that a * PFX b = PFX b * a.
Oops. Sorry about the URL title. I was trying to add that https://groups.google.com/forum/#!topic/scala-sips/ARVf1RLDw9U *might* be discussing a similar question, but got stuck trying to copy-n-paste on a tablet (I'm a heavy middle+right mouse button user) and failed to clean up properly when giving up.
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Although we know that PFX a * b = PFX(a*b), we don't know that * is commutative (ie a * b = b *a ) so we cannot assume that PFX(a*b)=PFX(b*a)
or that a * PFX b = PFX b * a.
Sorry about the URL title.
I was trying to add that https://groups.google.com/forum/#!topic/scala-sips/ARVf1RLDw9U *might* be discussing a similar question, but got stuck trying to copy-n-paste on a tablet (I'm a heavy middle+right mouse button user) and failed to clean up properly when giving up.