(*========================================================== ============================================================ TOPOLOGICAL FMAPS, HMAPS -  WITH TAGS AND EMBEDDINGS  PART 5:  characteristics, eqc, expf / L0, L_B  COMPLETE FOR DIM 0 (DIM 1 IN THE NEXT FILE): OK! ============================================================ ==========================================================*)
Require Export Jordan4.

Lemma nv_L_B:forall (m:fmap)(k:dim)(x:dart),
inv_hmap m -> succ m k x ->
let m1 := L (B m k x) k x (A m k x) in
nv m1 = nv m.