-\def\Longrightarrow{\lyxeq\kern-9mu\Rightarrow}
-\def\Longleftarrow{\Leftarrow\kern-9mu\lyxeq}
-\def\mapsto{\mapstochar\kern-12mu\rightarrow}
-\def\longmapsto{\mapstochar\kern-9mu\lyxbar\kern-11mu\rightarrow}
-\def\models{\vert\kern-7.5mu\lyxeq}
+\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}