Opened 5 years ago

Last modified 3 weeks ago

## #22149 new defect

# solve can't handle certain multi-equation settings

Reported by: | kcrisman | Owned by: | |
---|---|---|---|

Priority: | major | Milestone: | sage-9.4 |

Component: | symbolics | Keywords: | |

Cc: | Merged in: | ||

Authors: | Reviewers: | ||

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description

See this ask.sagemath question. Basically, at least in certain situations involving `abs()`

, you

var('x y a b') f=[1+y-a*abs_symbolic(x)==x, b*x==y]; f solve(f, [x, y])

gives boom, or more precisely

TypeError: cannot coerce arguments: no canonical coercion from <type 'list'> to Symbolic Ring

since it somehow is trying to make this into one object. But

assume(x>0) solve(f, [x, y])

gives not boom. So somehow our code for recognizing when we have a system of equations isn't working right in the first case. Note that

var('x y a b') f=[1+y-a*x==x, b*x==y] solve(f,[x,y]

apparently works fine.

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still the same in 9.4.beta4