This could challenge the dominance of established providers that levy much higher charges and usually require customers to pay for a landline.

For some commentators that amounts to a call for a new world currency that would challenge the dominance of the dollar.

The polarization became especially evident in the 1980s as a new generation of educated but religiously motivated local leaders emerged to challenge the dominance of the secularized political elite.

It has never challenged the dominance of four-stroke combustion engines but has replaced many two-stroke engines with a more efficient, powerful and cleaner system.

These challenged the dominance of the neorealist paradigms focus on states, mutually assured destruction and military security and briefly enabled a broader concept of security to emerge.