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Project-declaredLean 4.33.0-rc1

Polynomial elim Var correct

Cslib.SKI.Polynomial.elimVar_correct

Plain-language statement

Correctness for the elimVar algorithm, which provides the inductive step of the bracket abstraction algorithm. We induct backwards on the list, corresponding to applying the transformation from the inside out. Since we haven't defined reduction for polynomials, we substitute arbitrary terms for the inner variables.

computer sciencecomputabilityprogram semantics

Source project: Lean Computer Science Library

Person-level attribution pending.

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Project-declaredLean 4.33.0-rc1

Rice

Cslib.SKI.rice

Project documentation

Rice's theorem: no SKI term is a non-trivial predicate. More specifically, say a term P is a predicate if, for every term x, P · x reduces to either TT or FF. A predicate P is trivial if either it always reduces to true, or always to false. This version of Rice's theorem derives a contradiction from the existence of a predicate P and...

computer sciencecomputabilityprogram semantics

Source project: Lean Computer Science Library

Person-level attribution pending.

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