Re: [isabelle] Unify.matchers and term representation



On Tue, 30 Aug 2011, Lawrence Paulson wrote:

The unification algorithm operates on eta-expanded terms. Is there any compelling reason why you need them to be eta-contracted?

Larry is right that according to the natural order of things it is better to leave things as they are produced, and work conceptually with arbitrary representatives of the alpha/beta/eta equivalence classes.

In some boundary cases this might fails, because certain tools do not observe this equivalence. Here you can contract or expand manually to achieve a certain standard form, e.g. via Envir.eta_contract, Envir.beta_eta_contract, Patter.eta_long. The Thm module also provides some variants for actual theorems.


	Makarius





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