what are DP and DQ in Encryption by RSA in c# I want to know about these tags in RSA Encryption by private Key. when I use this code:

using (var provider = new RSACryptoServiceProvider(keySize))
    {
        publicKey = provider.ToXmlString(false);
        privateKey = provider.ToXmlString(true);
    }


It create this xml:

&lt;RSAKeyValue&gt;
   &lt;Modulus&gt;…&lt;/Modulus&gt;
   &lt;Exponent&gt;…&lt;/Exponent&gt;
   &lt;P&gt;…&lt;/P&gt;
   &lt;Q&gt;…&lt;/Q&gt;
   &lt;DP&gt;…&lt;/DP&gt;
   &lt;DQ&gt;…&lt;/DQ&gt;
   &lt;InverseQ&gt;…&lt;/InverseQ&gt;
   &lt;D&gt;…&lt;/D&gt;
&lt;/RSAKeyValue&gt;


I know that $p$ and $q$ are the primes number, but I dont know what are DP and DQ and why we need to InversQ and else... 

is anyone explain these items for encryption?
DP is $d\bmod{p-1}$, similarly DQ is $d\bmod{q-1}$. InverseQ is $q^{-1}\bmod{p}$.

These are used in applying the Chinese Remainder Theorem to RSA decryption, which is an optimization technique.