Introduce \newoperator

\newoperator mimics amsamth's \DeclareMathOperator; that is, it
defines a macro for an operator name which is consistent with the
standard operators like \max, \lim, and \lim w.r.t. appearance and
behavior.

The star variant \newoperator* permits the operator to take limits
like \max and \lim (e.g. \lim_{x\rightarrow\infty}) instead of a
subscript.

newnotation.sty

@@ -671,7 +671,46 @@
 	\@NNAddEntry{#3}{\string#3}{#4}{#7}{#8}%
 }
 
-
+% *************************************
+% \newoperator
+% *************************************
+%     Define macro for an operator name  and add entry to current group.
+%
+%   Arguments:
+%   1. star:      use limits (like \max or \lim)
+%   2. optional:  class name
+%   3. mandatory: macro name
+%   4. optional:  IGNORED
+%   5. optional:  IGNORED
+%   6. mandatory: replacement
+%   7. optional:  description for table of notation
+%   8. optional:  description of arguments for table of notation
+\DeclareDocumentCommand{\newoperator}{s o m O{0} o m O{} O{}}{%
+	% Check whether macro is already defined:
+	\ifdef{#3}%
+		{\PackageError{newnotation}{newoperator: Command '\string#3' already defined.}{Misspelled name?}}{}%
+	%
+	\@NNPrepareEntry{\string#3}%
+		\newrobustcmd{#3}[#4]{%
+			\IfNoValueTF{#2}%
+				% CLASS: no --------------------------------------------
+				%{no class defined}{class defined}
+				{\IfBooleanTF{#1}%
+					% STAR: yes
+					{\ensuremath{\operatorname*{#6}}}%
+					% STAR: no
+					{\ensuremath{\operatorname{{#6}}}}}%
+				% CLASS: yes -------------------------------------------
+				{\IfBooleanTF{#1}%
+					% STAR: yes
+					{\ensuremath{\operatorname*{\@nameuse{@NNClass#2}{#6}}}}%
+					% STAR: no
+					{\ensuremath{\operatorname{\@nameuse{@NNClass#2}{#6}}}}}%
+			\ifthenelse{\boolean{@NNInListMode}}{}{\protect\stepcounter{@NNCounter\string#3}}%
+			\xspace%
+		}%
+	\@NNAddEntry{#3}{\string#3}{0}{#7}{#8}%
+}
 
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