ohms law?

You're asking how Ohm's Law fits in with how you wire the subs?  When you wire the subs and connect them to the amplifier, you've placed an impedance load on the amp.  It is that impedance load that will enable the amplifier to produce power;  no load = no output.  That's where Ohm's Law comes into play.  Ohm's Law describes how the electrical forces power, resistance (impedance), current and voltage interact with each other.  These are steadfast, unchangeable physical laws.

In the chart you can see that the base formulae describe these interactions of the four forces.  P = I X E and E = I X R.  The groups of formulae listed below those are variations of those basics that will specifically lead you to an answer you might be looking for.

With your wiring concern, the amount of impedance load you wire those subs to will cause the amplifier to work in a specific way.  It is rated, that is, built for and tested to produce a limited amount of current.  All electrical devices have limitations.  A 1/2 ohm resistive load would cause it to produce more current 'I' than it was built to handle and so it would shut off or burn up trying to produce it.  Its 'R' limit is 1 ohm at the extreme limit and will accept any load at 1 ohm or higher.  That's why, with the subs you have, the lowest wiring impedance option is 2 ohms.