id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
14889,Equality in PowerSeriesRing can be unpredictable,darij,AlexGhitza,"I know this is unavoidable, but I'd say it should be better documented...
Over a finite field:
{{{
sage: K.__ = PowerSeriesRing(GF(5))
sage: u = K.gen()
sage: u ** 25
u^25
sage: u ** 25 == 0
False
sage: (1 + u) ** 25
1 + u^25
sage: (1 + u) ** 25 == 1
False
sage: (1 / (1 - u)) ** 25
1 + O(u^20)
sage: (1 / (1 - u)) ** 25 == 1
True
}}}
I suspect the last `True` is due to `1 / (1 - u)` being a dense series, which leads to Sage keeping precision at `O(u^20)` rather than moving to a higher exponent.",defect,new,minor,sage-6.4,algebra,,"power series, halting problem, discreteness, equality",,,,,N/A,,,,,
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