Summary: On Irrelevance and Extraction in Type Theory
INRIA, Team r2
PPS Lab, Paris
11th Agda Meeting
Awaji, Kansai, Japan
24 March 2010
Andreas Abel (INRIA) Typed Equality AIM XI 1 / 21
Irrelevance and Extraction in Type Theory
A type T is irrelevant if t, t : T implies t = t : T.
Three motivations to consider irrelevance:
1 More powerful type checkers.
More terms type check.
Less proof burden for the user.
2 More efficient type checkers.
Fewer terms to compare for equality.
Erasure of irrelevant parts in internal representation?
3 More dead-code elimination in program extraction.