2.4 – Relational Expressions
<relational expression> ->

    <primary a_relational expression> == <primary a_relational expression>
      |<primary a_relational expression> <> <primary a_relational expression>
      |<primary a_relational expression> > <primary a_relational expression>
      |<primary a_relational expression> < <primary a_relational expression>

   |<primary s_relational expression> == <primary s_relational expression>
      |<primary s_relational expression> <> <primary s_relational expression>
      |<primary s_relational expression> > <primary s_relational expression>
      |<primary s_relational expression> < <primary s_relational expression>

Let <RE>  <relational expression>
      <P_A_RE>  <primary a_relational expression>
      <P_S_RE>  <primary s_relational expression>

Left Factoring
<RE> -> <P_A_RE> <∆> <P_A_RE> | <P_S_RE> <∆> <P_S_RE>

<∆> -> == | <> | > | <

<primary a_relational expression> -> AVID_T | FPL_T | INL_T

<primary s_relational expression> -> <primary string expression>