Fix a grammar error.

diff --git a/include/deal.II/differentiation/sd/symengine_optimizer.h b/include/deal.II/differentiation/sd/symengine_optimizer.h
index 43c57468cd4747a8b51e5350d085dfb4c4251b31..aa27abe0bf2996f07037b7f78c8de891d4d84f9b 100644 (file)
--- a/include/deal.II/differentiation/sd/symengine_optimizer.h
+++ b/include/deal.II/differentiation/sd/symengine_optimizer.h
@@ -1947,7 +1947,7 @@ namespace Differentiation
 
       /**
        * A set of symbolic expressions to be optimized. It is required that
-       * the symbols on which these dependent functions be based are
+       * the symbols on which these dependent functions are based are
        * registered in the @p independent_variables_symbols map.
        */
       types::symbol_vector dependent_variables_functions;