X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Fnlibrary%2Ftopology%2Figft.ma;h=3c0ba7090406c43aef3f0cbd8df79d2143efd902;hb=89e21dbecca75a5320f50ecb53a39699f8ace8f1;hp=dcc7e9a81a86a15834228419c50ffdf9bf2b837b;hpb=7fd4f2f66fb8fe010bbd2bfe1f6b542c2da6c83f;p=helm.git diff --git a/helm/software/matita/nlibrary/topology/igft.ma b/helm/software/matita/nlibrary/topology/igft.ma index dcc7e9a81..3c0ba7090 100644 --- a/helm/software/matita/nlibrary/topology/igft.ma +++ b/helm/software/matita/nlibrary/topology/igft.ma @@ -240,7 +240,7 @@ reaching the end of the formalization, but we had to assume the proof of the extensionality of the `U_x` construction (while there is no need to assume the same property for `F_x`!). -The current version of the formaliztion uses `Id`. +The current version of the formalization uses `Id`. The standard library and the `include` command ---------------------------------------------- @@ -923,11 +923,11 @@ Thus the statement `Im[d(a,i)] ⊆ V` unfolds to That, up to rewriting with the equation defining `x`, is what we mean. Since we decided to use `Id` the rewriting always work (the elimination -prnciple for `Id` is Leibnitz's equality, that is quantified over +principle for `Id` is Leibnitz's equality, that is quantified over the context. The problem that arises if we decide to make `S` a setoid is that -`V` has to be extensional w.r.t. the equality of `S` (i.e. the charactestic +`V` has to be extensional w.r.t. the equality of `S` (i.e. the characteristic functional proposition has to quotient its input with a relation bigger than the one of `S`. @@ -1013,7 +1013,7 @@ there is still some work to do. D[retr-3] To use the equation defining `b` we have to eliminate `H`. Unfolding definitions in `x` tell us there is still something to do. The `nrewrite` -tactic is a shorcut for the elimination principle of the equlity. +tactic is a shortcut for the elimination principle of the equality. It accepts an additional argument `<` or `>` to rewrite left-to-right or right-to-left.