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Hi Phil, Francesco and Filippo,
Yes, as Filippo and Francesco say, Greek names were first proposed for these
two rules by Curry. He proposed
$\nu$ for the first rule and $\mu$ for the second. ("Combinatory Logic" Volume
1 p. 59.)
(Perhaps Curry also used them in one of his pre-1940 papers; I forget now.)
Happy summer!
Yours, Roger Hindley
----------------
On 3 Jul 2017, at 19:04, Philip Wadler <wad...@inf.ed.ac.uk> wrote:
> [ The Types Forum, http://lists.seas.upenn.edu/mailman/listinfo/types-list ]
>
> Reduction for the simply-typed call-by-value lambda calculus consists of
> the β rule,
>
> (λx.N)V ⟹ N[x:=V]
>
> and the congruence rules
>
> L ⟹ L′
> ------------
> L M ⟹ L′ M
>
> M ⟹ M′
> ------------
> V M ⟹ V M′
>
> Question: Is there a standard greek letter for naming the congruence rules,
> such as κ or γ? Or any other relevant naming convention?
>
> Cheers, -- P
>
>
> . \ Philip Wadler, Professor of Theoretical Computer Science
> . /\ School of Informatics, University of Edinburgh
> . / \ http://homepages.inf.ed.ac.uk/wadler/
> The University of Edinburgh is a charitable body, registered in
> Scotland, with registration number SC005336.
