Solving a single equation for multiple variables doesn't work with assumptions
As reported in Ask SageMath question #46915:
sage: x,y = var('x,y', domain=RR)
sage: solve(x == 0, x, y)
gives an error message (unlike variants without assumptions, solving for a single variable, or adding a dummy equation).
It can be traced as follows: in sage/symbolic/relation.py
the function solve
calls _solve_expression
to handle the single expression case. This (by default) uses the Maxima interface to create an initial list of solutions X
, which is then filtered according to assumptions()
. This filtering assumes that each solution in X
is a single equation (it calls .lhs()
on elements of X
), which is not true in the case of multiple variables.
Change History (9)
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Moving open critical and blocker issues to the next release milestone (optimistically).