DEFINITION csubt_clear_conf()
TYPE =
       ∀g:G.∀c1:C.∀c2:C.(csubt g c1 c2)→∀e1:C.(clear c1 e1)→(ex2 C λe2:C.csubt g e1 e2 λe2:C.clear c2 e2)
BODY =
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