Check IN WHICH CASE symbolic logical expression is true

Is it possible to get the conditions under which an expression would be true. Example:

syms a b c
assume(a > 0)
c = a+ b
isAlways(c >0 )

Warning: Unable to prove '0 < a + b'. 
> In symengine
  In sym/isAlways (line 42)
  In LiveEditorEvaluationHelperEID289025349 (line 314)
  In matlab.internal.editor.evaluateRegions
  In matlab.internal.editor.EvaluationOutputsService.evalRegions 

Now I would like to receive the information that c > 0 if b >= 0.

That possible?

Answer 1

[Hendrik Lorenz]

Well what I stated is true: c > 0 if b >= 0 Although it is not true that b >= 0 if c > 0 right. But you got what I meant. Thanks for the answer!

Answer 2

[Steven Lord]

No, that's not possible because as you've stated your solution it's not true. c can be greater than 0 even if b is negative.

a = 1;
b = -0.5;
c = a+b

For c to be greater than 0, b must be greater than -a which does not necessarily require it to be greater than 0.You can ask solve to return conditions.

syms a b c
assume(a > 0)
c = a + b
[S, params, conditions] = solve(c > 0, b, 'ReturnConditions', true)

b can be any value x such that -a < x.