does elemental penetration affect ailment application?

I know that ailment application takes into consideration pre mitigation damage; but penetration does not belong to the "target" but to the "caster" (in the sense that is not a debuff).
So, i would like to know, does penetration increase ailment application?

Depends on what ailment you're talking about.

Elemental penetration should affect Chill, freeze, shock, and electrocute buildup.

Elemental penetration AND elemental resistance DO NOT affect ignite application.

The ignite is based on the PRE-MITIGATED DMG (No penetration, No resistance) the monster would take. So monsters are treated as having 0 fire resistance when determining the ignite.

If the monster is ignited, then the resistance of the monster + ur curses/exposure/etc will determine the magnitude of the ignite (how much dmg it takes over time). Penetration DOES NOT affect ignite at all no matter what.