I don't think any of the Master Items (Dimensions & Measures) can be referenced in any of the formulas. It would make a nice Idea, i.e. a suggestion for a future development.
For now, you need to use the actual field names or calculations in formulas. If you need to use the same calculation several times, you can store the calculation in a variable and then reference the variable in a $-sign expansion. For example:
vMasterDim = 'IF(A=B, 'Good', 'Bad')
IF( '$(vMasterDim)' = 'Good', Green(), Red())
This is overly simplified, of course, but it should get the message across.
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