-\def\longleftrightarrow{\leftarrow\kern-2mm\rightarrow}
-\def\Longleftrightarrow{\Leftarrow\kern-2mm\Rightarrow}
-\def\doteq{\stackrel{\cdot}{\=}}
-\def\longrightarrow{\lyxbar\kern-2mm\rightarrow}
-\def\longleftarrow{\leftarrow\kern-2mm\lyxbar}
-\def\mapsto{\mapstochar\kern-2mm\rightarrow}
-\def\longmapsto{\mapstochar\kern-2mm\lyxbar\kern-6mu\rightarrow}
-\def\Longrightarrow{\lyxeq\kern-2mm\Rightarrow}
-\def\Longleftarrow{\Leftarrow\kern-2mm\lyxeq}
-\def\models{\vert\kern-2mm\lyxeq}
-\def\hookrightarrow{\lhook\kern-2mm\rightarrow}
-\def\hookleftarrow{\leftarrow\kern-2mm\rhook}
-\def\bowtie{\triangleright\kern-2mm\triangleleft}
+\def\neq{\not=}
+\def\ne{\not=}
+\def\notin{\not\in}
+\def\slash{/}
+
+\def\longleftrightarrow{\leftarrow\kern-12.5mu\rightarrow}
+\def\Longleftrightarrow{\Leftarrow\kern-12.5mu\Rightarrow}
+\def\iff{\Leftarrow\kern-12.5mu\Rightarrow}
+\def\doteq{\stackrel{\cdot}{=}}
+
+iffont cmsy
+\def\longrightarrow{\lyxbar\kern-11mu\rightarrow}
+\def\longleftarrow{\leftarrow\kern-11mu\lyxbar}
+\def\Longrightarrow{\lyxeq\kern-9.5mu\Rightarrow}
+\def\Longleftarrow{\Leftarrow\kern-9.5mu\lyxeq}
+\def\implies{\Longrightarrow}
+\def\mapsto{\mapstochar\kern-9mu\rightarrow}
+\def\longmapsto{\mapstochar\kern-6mu\lyxbar\kern-11mu\rightarrow}
+\def\models{\vert\kern-7mu\lyxeq}
+endif
+iffont cmm
+\def\hookrightarrow{\lhook\kern-12mu\rightarrow}
+\def\hookleftarrow{\leftarrow\kern-12mu\rhook}
+\def\bowtie{\triangleright\kern-6mu\triangleleft}
+endif
+iffont msa