equal
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inserted
replaced
134 by (simp add: NSLIM_def) |
134 by (simp add: NSLIM_def) |
135 |
135 |
136 subsubsection \<open>Equivalence of @{term filterlim} and @{term NSLIM}\<close> |
136 subsubsection \<open>Equivalence of @{term filterlim} and @{term NSLIM}\<close> |
137 |
137 |
138 lemma LIM_NSLIM: |
138 lemma LIM_NSLIM: |
139 assumes f: "f -- a --> L" shows "f \<midarrow>a\<rightarrow>\<^sub>N\<^sub>S L" |
139 assumes f: "f \<midarrow>a\<rightarrow> L" shows "f \<midarrow>a\<rightarrow>\<^sub>N\<^sub>S L" |
140 proof (rule NSLIM_I) |
140 proof (rule NSLIM_I) |
141 fix x |
141 fix x |
142 assume neq: "x \<noteq> star_of a" |
142 assume neq: "x \<noteq> star_of a" |
143 assume approx: "x \<approx> star_of a" |
143 assume approx: "x \<approx> star_of a" |
144 have "starfun f x - star_of L \<in> Infinitesimal" |
144 have "starfun f x - star_of L \<in> Infinitesimal" |
162 thus "starfun f x \<approx> star_of L" |
162 thus "starfun f x \<approx> star_of L" |
163 by (unfold approx_def) |
163 by (unfold approx_def) |
164 qed |
164 qed |
165 |
165 |
166 lemma NSLIM_LIM: |
166 lemma NSLIM_LIM: |
167 assumes f: "f \<midarrow>a\<rightarrow>\<^sub>N\<^sub>S L" shows "f -- a --> L" |
167 assumes f: "f \<midarrow>a\<rightarrow>\<^sub>N\<^sub>S L" shows "f \<midarrow>a\<rightarrow> L" |
168 proof (rule LIM_I) |
168 proof (rule LIM_I) |
169 fix r::real assume r: "0 < r" |
169 fix r::real assume r: "0 < r" |
170 have "\<exists>s>0. \<forall>x. x \<noteq> star_of a \<and> hnorm (x - star_of a) < s |
170 have "\<exists>s>0. \<forall>x. x \<noteq> star_of a \<and> hnorm (x - star_of a) < s |
171 \<longrightarrow> hnorm (starfun f x - star_of L) < star_of r" |
171 \<longrightarrow> hnorm (starfun f x - star_of L) < star_of r" |
172 proof (rule exI, safe) |
172 proof (rule exI, safe) |
188 qed |
188 qed |
189 thus "\<exists>s>0. \<forall>x. x \<noteq> a \<and> norm (x - a) < s \<longrightarrow> norm (f x - L) < r" |
189 thus "\<exists>s>0. \<forall>x. x \<noteq> a \<and> norm (x - a) < s \<longrightarrow> norm (f x - L) < r" |
190 by transfer |
190 by transfer |
191 qed |
191 qed |
192 |
192 |
193 theorem LIM_NSLIM_iff: "(f -- x --> L) = (f \<midarrow>x\<rightarrow>\<^sub>N\<^sub>S L)" |
193 theorem LIM_NSLIM_iff: "(f \<midarrow>x\<rightarrow> L) = (f \<midarrow>x\<rightarrow>\<^sub>N\<^sub>S L)" |
194 by (blast intro: LIM_NSLIM NSLIM_LIM) |
194 by (blast intro: LIM_NSLIM NSLIM_LIM) |
195 |
195 |
196 |
196 |
197 subsection \<open>Continuity\<close> |
197 subsection \<open>Continuity\<close> |
198 |
198 |
213 lemma isNSCont_NSLIM_iff: "(isNSCont f a) = (f \<midarrow>a\<rightarrow>\<^sub>N\<^sub>S (f a))" |
213 lemma isNSCont_NSLIM_iff: "(isNSCont f a) = (f \<midarrow>a\<rightarrow>\<^sub>N\<^sub>S (f a))" |
214 by (blast intro: isNSCont_NSLIM NSLIM_isNSCont) |
214 by (blast intro: isNSCont_NSLIM NSLIM_isNSCont) |
215 |
215 |
216 text\<open>Hence, NS continuity can be given |
216 text\<open>Hence, NS continuity can be given |
217 in terms of standard limit\<close> |
217 in terms of standard limit\<close> |
218 lemma isNSCont_LIM_iff: "(isNSCont f a) = (f -- a --> (f a))" |
218 lemma isNSCont_LIM_iff: "(isNSCont f a) = (f \<midarrow>a\<rightarrow> (f a))" |
219 by (simp add: LIM_NSLIM_iff isNSCont_NSLIM_iff) |
219 by (simp add: LIM_NSLIM_iff isNSCont_NSLIM_iff) |
220 |
220 |
221 text\<open>Moreover, it's trivial now that NS continuity |
221 text\<open>Moreover, it's trivial now that NS continuity |
222 is equivalent to standard continuity\<close> |
222 is equivalent to standard continuity\<close> |
223 lemma isNSCont_isCont_iff: "(isNSCont f a) = (isCont f a)" |
223 lemma isNSCont_isCont_iff: "(isNSCont f a) = (isCont f a)" |