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15 include "delayed_updating/syntax/path.ma".
16 include "delayed_updating/notation/functions/class_p_0.ma".
17 include "ground/lib/subset.ma".
18 include "ground/xoa/ex_1_2.ma".
20 (* PROPER CONDITION FOR PATH ************************************************)
22 definition ppc: predicate path ā
27 "proper condition (path)"
30 (* Basic constructions ******************************************************)
32 lemma ppc_lcons (l) (q): lāq Ļµ š.
36 (* Basic inversions ********************************************************)
38 lemma ppc_inv_lcons (p):
39 p Ļµ š ā āāl,q. lāq = p.
42 | #l #q #_ /2 width=3 by ex1_2_intro/