Optional Generic Types

Is there a better way to write this? As one class perhaps, instead of two.

using System;

namespace SnippetTool.Repositories
{
    public abstract class ARepository<TProvider> where TProvider : class
    {
        protected TProvider Provider { get; set; }

        protected ARepository(TProvider provider)
        {
            if (provider == null)
                throw new ArgumentNullException("provider");

            Provider = provider;
        }
    }

    public abstract class ARepository<TProvider, TValidator> : ARepository<TProvider> where TProvider : class where TValidator : class
    {
        protected TValidator Validator { get; set; }

        protected ARepository(TProvider provider, TValidator validator) : base(provider)
        {
            Validator = validator;
        }
    }
}