deletions | additions       diff --git a/layout.md b/layout.md  index cf58f8c..bbc9628 100644  --- a/layout.md  +++ b/layout.md 
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Subsituting_4_into_1_vec__.tex  From_5_we_can_see__.tex  Inverse_is_also_true_if__.tex  vec_v_t_Delta_t__.tex vec_x_t_Delta_t__1.tex