+%%%%%%%% \ltjalchar<number>, \ltjjachar<number>
+\let\ltj@@origchar=\char
+\protected\def\ltj@alljachar{\relax
+ \csname ltj@kcat0\endcsname=0
+ \csname ltj@kcat1\endcsname=0
+ \csname ltj@kcat2\endcsname=0
+ \csname ltj@kcat3\endcsname=0
+ \csname ltj@kcat4\endcsname=0
+ \csname ltj@kcat5\endcsname=0
+ \csname ltj@kcat6\endcsname=0 }
+\protected\def\ltj@allalchar{\relax
+ \csname ltj@kcat0\endcsname="7FFFFFFF %"
+ \csname ltj@kcat1\endcsname="7FFFFFFF %"
+ \csname ltj@kcat2\endcsname="7FFFFFFF %"
+ \csname ltj@kcat3\endcsname="7FFFFFFF %"
+ \csname ltj@kcat4\endcsname="7FFFFFFF %"
+ \csname ltj@kcat5\endcsname="7FFFFFFF %"
+ \csname ltj@kcat6\endcsname="7FFFFFFF }%"
+
+\protected\def\ltjjachar{\afterassignment\ltj@@jachar\ltj@tempcnta}
+\def\ltj@@jachar{{\directlua{tex.globaldefs = 0}\ltj@alljachar\ltj@@origchar\ltj@tempcnta}}
+\protected\def\ltjalchar{\afterassignment\ltj@@alchar\ltj@tempcnta}
+\def\ltj@@alchar{{\directlua{tex.globaldefs = 0}\ltj@allalchar\ltj@@origchar\ltj@tempcnta}}
+
+%%%%%%%% \ltjsetmathletter<number>, \ltjunsetmathletter<number>
+\protected\def\ltjsetmathletter#1{\directlua{luatexja.math.is_math_letters[#1]=true}}
+\protected\def\ltjunsetmathletter#1{\directlua{luatexja.math.is_math_letters[#1]=false}}