6.2. RiemannSimplify

This function combines most of the functionalities of Invar` and it is certainly the most important tool for the user. Essentially RiemannSimplify is equivalent to the process:
    rexpr -> (RiemannToInv) -> rinv -> (InvSimplify) -> canon rinv -> (InvToRiemann) -> canon rexpr
This means that RiemannSimplify requires three additional arguments:
    - a metric for RiemannToInv
    - a simplification level for InvSimplify
    - the curvature-relations switch to Ricci.
All three of them have default values, so that the function can be used with a single argument.

Example:

In[127]:=

rexpr = RandomRiemannMonomial[{0, 2, 2}]

Out[127]=

Scalar[R_ (h ef)^( b  ) R_ ( g     ; a)^(g cd ; e  ) R_ (db     ; c)^(  fh ; a  )]

In[128]:=

RiemannSimplify[%]

Out[128]=

0

In[129]:=

? RiemannSimplify

In[130]:=

RiemannSimplify[RandomRiemannMonomial[{6}], 4, True, metric]

Reading InvRules for step 1 and case {6}

Reading InvRules for step 1 and case {1, 3}

Reading InvRules for step 1 and case {2, 2}

Out[130]=

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