Skip to content

Commit

Permalink
fix naming
Browse files Browse the repository at this point in the history
  • Loading branch information
affeldt-aist committed Sep 28, 2023
1 parent 066d877 commit a6b1d80
Showing 1 changed file with 14 additions and 11 deletions.
25 changes: 14 additions & 11 deletions theories/exp.v
Original file line number Diff line number Diff line change
Expand Up @@ -664,7 +664,16 @@ move=> a1 x y xy.
by rewrite /powR gt_eqF ?(lt_le_trans _ a1)// ler_expR ler_wpmul2r ?ln_ge0.
Qed.

Lemma gt0_ler_powR (r : R) : 0 <= r ->
Lemma powR_injective r : 0 < r -> {in Num.nneg &, injective (powR ^~ r)}.
Proof.
move=> r0 x y x0 y0; rewrite /powR; case: ifPn => [/eqP ->|xneq0].
by case: ifPn => [/eqP ->//|_ /eqP]; rewrite (gt_eqF r0) eq_sym expR_eq0.
case: ifPn => [/eqP -> /eqP|yneq0]; first by rewrite (gt_eqF r0) expR_eq0.
by move/expR_inj/mulfI => /(_ (negbT (gt_eqF r0))); apply: ln_inj;
rewrite posrE lt_neqAle eq_sym (xneq0,yneq0).
Qed.

Lemma ge0_ler_powR (r : R) : 0 <= r ->
{in Num.nneg &, {homo powR ^~ r : x y / x <= y >-> x <= y}}.
Proof.
rewrite le_eqVlt => /predU1P[<- x y _ _ _|]; first by rewrite !powRr0.
Expand All @@ -676,19 +685,10 @@ move=> /predU1P[->//|xy]; first by rewrite eqxx.
by apply/orP; right; rewrite /powR !gt_eqF// ltr_expR ltr_pmul2l// ltr_ln.
Qed.

Lemma powR_injective r : 0 < r -> {in Num.nneg &, injective (powR ^~ r)}.
Proof.
move=> r0 x y x0 y0; rewrite /powR; case: ifPn => [/eqP ->|xneq0].
by case: ifPn => [/eqP ->//|_ /eqP]; rewrite (gt_eqF r0) eq_sym expR_eq0.
case: ifPn => [/eqP -> /eqP|yneq0]; first by rewrite (gt_eqF r0) expR_eq0.
by move/expR_inj/mulfI => /(_ (negbT (gt_eqF r0))); apply: ln_inj;
rewrite posrE lt_neqAle eq_sym (xneq0,yneq0).
Qed.

Lemma gt0_ltr_powR (r : R) : 0 < r ->
{in Num.nneg &, {homo powR ^~ r : x y / x < y >-> x < y}}.
Proof.
move=> r0 x y x0 y0 xy; have := gt0_ler_powR (ltW r0) x0 y0 (ltW xy).
move=> r0 x y x0 y0 xy; have := ge0_ler_powR (ltW r0) x0 y0 (ltW xy).
rewrite le_eqVlt => /orP[/eqP/(powR_injective r0 x0 y0)/eqP|//].
by rewrite lt_eqF.
Qed.
Expand Down Expand Up @@ -803,6 +803,9 @@ Qed.
End PowR.
Notation "a `^ x" := (powR a x) : ring_scope.

#[deprecated(since="mathcomp-analysis 0.6.5", note="renamed `ge0_ler_powR`")]
Notation gt0_ler_powR := ge0_ler_powR.

Section poweR.
Local Open Scope ereal_scope.
Context {R : realType}.
Expand Down

0 comments on commit a6b1d80

Please sign in to comment.