diff --git a/hott/homotopy/circle.hlean b/hott/homotopy/circle.hlean index 57841b5e8..5bdf06cfb 100644 --- a/hott/homotopy/circle.hlean +++ b/hott/homotopy/circle.hlean @@ -8,9 +8,9 @@ Declaration of the circle import .sphere import types.bool types.int.hott types.equiv -import algebra.homotopy_group algebra.hott +import algebra.homotopy_group algebra.hott .connectedness -open eq susp bool sphere_index is_equiv equiv equiv.ops is_trunc pi algebra +open eq susp bool sphere_index is_equiv equiv equiv.ops is_trunc pi algebra homotopy definition circle : Type₀ := sphere 1 @@ -269,6 +269,23 @@ namespace circle induction H', reflexivity} end + definition is_trunc_circle [instance] : is_trunc 1 S¹ := + begin + apply is_trunc_succ_of_is_trunc_loop, + { exact unit.star}, + { intro x, apply is_trunc_equiv_closed_rev, apply eq_equiv_Z} + end + + definition is_conn_circle [instance] : is_conn 0 S¹ := + begin + fapply is_contr.mk, + { exact tr base}, + { intro x, induction x with x, + induction x, + { reflexivity}, + { apply is_prop.elimo}} + end + definition circle_mul [reducible] (x y : S¹) : S¹ := begin induction x,