Index: library/nx/nx.tcl
===================================================================
diff -u -rbb1a4116720d5f205e44ec71f03857a340751fc3 -ra8c1439e8965d31f21dc61903ffbd3bc1c2e7635
--- library/nx/nx.tcl	(.../nx.tcl)	(revision bb1a4116720d5f205e44ec71f03857a340751fc3)
+++ library/nx/nx.tcl	(.../nx.tcl)	(revision a8c1439e8965d31f21dc61903ffbd3bc1c2e7635)
@@ -2276,7 +2276,7 @@
   ::nx::VariableSlot public method value=add {obj prop value {pos 0}} {
     if {![:isMultivalued]} {
       #puts stderr "... vars [[self] info vars] // [[self] eval {set :multiplicity}]"
-      return -code error "property $prop of [set :domain] ist not multivalued"
+      return -code error "property $prop of [set :domain] is not multivalued"
     }
     if {[::nsf::var::exists $obj $prop]} {
       ::nsf::var::set $obj $prop [linsert [::nsf::var::set $obj $prop] $pos $value]