Calculi based on an equal sign are called algebras. ⇒ The Equal Sign
The algebraic style of Boundary Math includes maintaining equality by transforming containment relations that match clearly defined patterns. If a containment pattern does not match a rule, then it cannot be changed. More generally the Axiomatic Principle constrains what can be done within a formal system.
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of James algebra, the transformations that are designed to define the behavior of the arithmetic and algebra of numbers.
Tai-Danae Bradley's thesis arxiv 
concerns the equation: Algebra + Statistics = ?
See Crystal Clear
This was an amazing innovation which applied a Mixture of Algebra and Geometry to the study of language, that is, language in its role as the medium of argumentation.