Function(signal) generator. Help!

Audioguru said:

Vo1 is a positive-going and negative-going ramp making a triangle wave.
It rises or falls far enough to make the (+) input of the Schmitt trigger opamp slightly higher or lower than the voltage on the (-) input (4.94V) as I explained in my last reply to make the threshold voltage of the triangle wave.

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Ok. I understand this as you said in your last reply regarding the Schmitt Trigger, but on the other side where is the integrator how is Vo1 calculated regarding R4 and C4? For example the current through R4 equals the current through C2? Is Vo1(t) in this case equal to integral from 0 to t of the voltage input of t + Vo1(0)?

And about the schmitt trigger, when Vp reaches the point where Vn=4.94, then the output changes(switches). So the upper and lower trigger level is Vn? I mean whenever Vp passes Vn the output goes high or low? Is this correct?
Here is a graph