eqn_block is for a block-level equation. The equation (and possibly the equation identifier, such as a number) is the only content in the block.
eqn_block is a specialization of p. It can contain MathML.
+ topic/p d4p-formatting-d/eqn_block
<p>The following equation is an example of arithmetic.</p> <eqn_block>2 + 2 = 4</eqn_block>