"Unequal sameness theory (UST) addresses modeling of the sameness, or equivalence, of unequal quantities. Twins have the same parents, but are not equal to each other. All tofu tastes the same - but is acquired at different (unequal) costs. UST also considers the converse proposition. Two equal quantities may not be the same. Four quarters, for example, is equal to one dollar. Four quarters, though, are clearly not the same as a dollar bill. In terms of sameness, 4 is not equal to 1. In terms of equality, 4=1." Excerpt from Unequal Sameness Theory: Towards Precise Understanding of Contradictory Equivalence by R.J. Marks II
The precise modeling of items that are unequal, though still the same, is the goal of UST.
An example from calculus is Ocum's derivative.
Contributors to UST include ...
George Orwell, who wrote "some animals are more equal than others"
Georg Cantor shows that, even though they are unequal, a 2x2 square is the same as a 1x1 square.
Robert Boughb, who demonstrated that the limit as 2 approaches 1 is one.