diff options
| author | Guillaume Melquiond | 2015-07-29 18:46:18 +0200 |
|---|---|---|
| committer | Guillaume Melquiond | 2015-07-29 18:46:40 +0200 |
| commit | f7180b6a33349ded33269d3ba25a9e0ed75d1896 (patch) | |
| tree | 9fd14f23dd87fc11af7278978596e0f68644d51d | |
| parent | 8506a4d60417ce498ce4525de044a6a590a5e922 (diff) | |
Improve the FAQ a bit.
| -rw-r--r-- | doc/faq/FAQ.tex | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/doc/faq/FAQ.tex b/doc/faq/FAQ.tex index b03aa64090..899b196350 100644 --- a/doc/faq/FAQ.tex +++ b/doc/faq/FAQ.tex @@ -849,7 +849,7 @@ mapped to {\Prop}. Use some theorem or assumption or use the {\split} tactic. \begin{coq_example} -Goal forall A B:Prop, A->B-> A/\B. +Goal forall A B:Prop, A -> B -> A/\B. intros. split. assumption. @@ -859,16 +859,25 @@ Qed. \Question{My goal contains a conjunction as an hypothesis, how can I use it?} -If you want to decompose your hypothesis into other hypothesis you can use the {\decompose} tactic: +If you want to decompose a hypothesis into several hypotheses, you can +use the {\destruct} tactic: \begin{coq_example} -Goal forall A B:Prop, A/\B-> B. +Goal forall A B:Prop, A/\B -> B. intros. -decompose [and] H. +destruct H as [H1 H2]. assumption. Qed. \end{coq_example} +You can also perform the destruction at the time of introduction: + +\begin{coq_example} +Goal forall A B:Prop, A/\B -> B. +intros A B [H1 H2]. +assumption. +Qed. +\end{coq_example} \Question{My goal is a disjunction, how can I prove it?} @@ -878,7 +887,7 @@ reasoning step, use the {\tt classic} axiom to prove the right part with the ass that the left part of the disjunction is false. \begin{coq_example} -Goal forall A B:Prop, A-> A\/B. +Goal forall A B:Prop, A -> A\/B. intros. left. assumption. @@ -890,14 +899,14 @@ An example using classical reasoning: \begin{coq_example} Require Import Classical. -Ltac classical_right := -match goal with -| _:_ |-?X1 \/ _ => (elim (classic X1);intro;[left;trivial|right]) +Ltac classical_right := +match goal with +| _:_ |- ?X1 \/ _ => (elim (classic X1);intro;[left;trivial|right]) end. -Ltac classical_left := -match goal with -| _:_ |- _ \/?X1 => (elim (classic X1);intro;[right;trivial|left]) +Ltac classical_left := +match goal with +| _:_ |- _ \/ ?X1 => (elim (classic X1);intro;[right;trivial|left]) end. @@ -1199,7 +1208,7 @@ Qed. \end{coq_example} -\Question{My goal is an inequality on integers in Presburger's arithmetic (an expression build from +,-,constants and variables), how can I prove it?} +\Question{My goal is an inequality on integers in Presburger's arithmetic (an expression build from $+$, $-$, constants, and variables), how can I prove it?} \begin{coq_example} |
