(Leftmost-Outermost) Beta Reduction is Invariant, Indeed
@article{Accattoli2016LeftmostOutermostBR, title={(Leftmost-Outermost) Beta Reduction is Invariant, Indeed}, author={Beniamino Accattoli and Ugo Dal Lago}, journal={Log. Methods Comput. Sci.}, year={2016}, volume={12} }
Slot and van Emde Boas' weak invariance thesis states that reasonable machines can simulate each other within a polynomially overhead in time. Is lambda-calculus a reasonable machine? Is there a way to measure the computational complexity of a lambda-term? This paper presents the first complete positive answer to this long-standing problem. Moreover, our answer is completely machine-independent and based over a standard notion in the theory of lambda-calculus: the length of a leftmost-outermost…
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