include "basic_2/unfold/ltpss.ma".
-(* LOCAL ENVIRONMENT THINNING ***********************************************)
+(* BASIC LOCAL ENVIRONMENT THINNING *****************************************)
definition thin: nat → nat → relation lenv ≝
λd,e,L1,L2. ∃∃L. L1 [d, e] ▶* L & ⇩[d, e] L ≡ L2.
-interpretation "thinning (local environment)"
+interpretation "basic thinning (local environment)"
'TSubst L1 d e L2 = (thin d e L1 L2).
(* Basic properties *********************************************************)