Statements of fact can contradict AutoMathic's current working knowledge.  If the contradiction involves a single variable, as happens when redefining a single quantity, all dependent variables will be undefined (with some possibly redefined) to prevent leaving things in a contradictory state.

> !list

 (Eq. 1)
           A + B = 21

   Where 'A' stands for ALPHA
   Where 'B' stands for BETA

       A = 14
       B = 7

Anything else?

Below, alpha is redefined to be three (instead of its current working value of 14), and beta
automatically gets recalculated:

Anything else?

> How much is beta when alpha is three?

   (Find B)

               A = 3

       A = 3

 Undefining 'B' ...

   Solving for B:

           A + B = 21

              B = 21 - A

       B = 18

   18 is BETA.     

If a statement of fact involving multiple variables contradicts AutoMathic's current working knowledge, the statement will be accepted, but the user will be warned that the resulting equation is "Overdetermined, and the system is Inconsistent".  This type of inconsistency must be resolved by the user in order to have accurate results!

In this example, the equation does not agree with its predefined variables:

> P=1; Q=1; P+Q=3

   Let 'P' stand for "P"

               P = 1

       P = 1

   Let 'Q' stand for "Q"

               Q = 1

       Q = 1

           P + Q = 3

 * Warning: Equation 'P+Q=3' is Overdetermined, and the system is Inconsistent.

Since the equation "P+Q=3" contradicted the working values of the variables "P" and "Q", a warning was given.  After that message, any answers given or questions posed should be considered invalid until the contradiction is resolved!

Resolving Contradictions

Once an inconsistency has been detected and reported, there are essentially three options for resolving it:

  1. Removing (and perhaps redefining) the inconsistent equation.
e.g.   > !list
> !remove 1
> P+Q=2
  1. Manually redefining one or more of the equation's variables to match the equation itself.  This will force automatic clearing and recalculation of other dependent variables if necessary and wherever possible.
e.g.   > P equals 2

e.g.  > Q equals 2
  1. Automatically redefining one or more of the equation's variables.  This will force automatic recalculation of the specified variable(s) if necessary and wherever possible.
e.g.   > !clear P

e.g.  > !clear Q

e.g.  > !clear P Q

Since the appropriate way of resolving an inconsistency is very dependent on the given situation, AutoMathic does not automatically do anything more than detect and report the inconsistency...  It is the user's responsibility to resolve it.