!!! Overview
[{$pagename}] ([RFC 4517]) [MatchingRule] compares an [Assertion Value] of the [OID] syntax to an [Attribute Value] of a syntax (e.g., the  [Attribute Type Description], [DIT Content Rule Description], [LDAP Syntax Description], [Matching Rule Description], [Matching Rule Use Description], [Name Form Description], or [Object Class Description] syntax) whose corresponding ASN.1 type is a SEQUENCE with a mandatory first component of the [OBJECT IDENTIFIER|OID] [ASN.1] type.

Note that the assertion syntax of this matching rule differs from the attribute syntax of attributes for which this is the equality matching rule.

The rule evaluates to TRUE if and only if the assertion value matches the first component of the attribute value using the rules of objectIdentifierMatch.

The LDAP definition for the objectIdentifierFirstComponentMatch matching rule is:
%%prettify 
{{{
( 2.5.13.30 NAME 'objectIdentifierFirstComponentMatch'
    SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 
)
}}} 
/%

The objectIdentifierFirstComponentMatch rule is an [EQUALITY] [MatchingRule].  When using objectIdentifierFirstComponentMatch to compare two attribute values (of an applicable syntax), an assertion value must first be derived from one of the attribute values.  An assertion value can be derived from an attribute value by taking the first component of that attribute value.

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]