sfja/sfja — Issue #11: subject reduction/expansion の訳語
Author: leque
Created: 2011-10-19 10:35:43+00:00
State: open

Types の Type Preservation の節冒頭。

> This theorem is often called the *subject reduction* property, because it tells us what happens when the "subject" of the typing relation is reduced. This terminology comes from thinking of typing statements as sentences, where the term is the subject and the type is the predicate.

ググったところでは定訳は見つけられず。そのまま subject reduction とする人が多いか。

reduction は「簡約」でよいとして、 subject は語源にしたがい「主語」とするか。
RDF triple でも subject を「主語」とする？

subject expansion は Types / Additional Exercises

> Exercise: 2 stars, recommended (subject_expansion)
> Having seen the subject reduction property, it is reasonable to wonder whether the opposity property — subject *expansion* — also holds.

こちらは未考。