diff options
Diffstat (limited to 'src/Core/Term.idr')
| -rw-r--r-- | src/Core/Term.idr | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/Core/Term.idr b/src/Core/Term.idr index e52545d..182e1ea 100644 --- a/src/Core/Term.idr +++ b/src/Core/Term.idr @@ -81,3 +81,11 @@ expandShift : (thin : sx `Thins` sy) -> expand (shift t thin) = wkn (expand t) thin expandShift (term `Over` thin') thin = sym $ wknHomo term thin' thin + +export +shiftHomo : + (t : Thinned sx) -> + (thin1 : sx `Thins` sy) -> + (thin2 : sy `Thins` sz) -> + shift (shift t thin1) thin2 = shift t (thin2 . thin1) +shiftHomo (term `Over` thin) thin1 thin2 = cong (term `Over`) $ compAssoc thin2 thin1 thin |