I’ll answer each part simply, with note of Digambar / Shwetambar where it differs.

---

1. After kevalgyan, does a kevalgyani experience sukh (happiness)?

Yes – but not worldly happiness.

• When kevalgyan arises, the four ghāti karmas are totally destroyed, so the soul’s own nature shines fully:

anant jñān, anant darshan, anant vīrya, anant sukh (infinite knowledge, perception, energy, bliss).

• This anant sukh is:

- not from body, senses, or situations - not like “I feel happy because something good happened” - it is swabhāvik ānanda – natural, constant bliss of the pure soul.

About bodily pleasure–pain (vedanīya karma):

• Technically, vedanīya karma is still present until the soul leaves the body (becomes Siddha).
• But at kevalgyan stage, its effect does not disturb the kevali’s inner bliss or equanimity.

Digambar view (simple):

• Kevali does not feel hunger, thirst, bodily pain or pleasure at all.
• Only pure, uninterrupted spiritual bliss.

Shwetambar view (simple):

• Body may still have natural states (heat–cold, etc.),

but the kevali remains totally unaffected, without inner joy–sorrow from them.

• Real sukh is only the inner infinite bliss of the soul.

So: A kevalgyani is always in perfect, infinite bliss – not rising or falling with any external condition.

---

2. Does a kevalgyani lie down?

Here Digambar and Shwetambar differ more clearly.

Digambar tradition:

• After kevalgyan, the Arihant is in continuous, motionless meditation (kāyotsarga).
• Common description:

- does not walk, sit, or lie down like ordinary beings - no ordinary bodily movements

• So according to strict Digambar doctrine,

kevali does not lie down or change posture for bodily comfort.

Shwetambar tradition:

• Tirthankar / kevali:

- walks, sits, lies down, takes alms, gives discourses, etc. - follows all rules of conduct, but with complete detachment.

• So according to Shwetambar,

kevali may lie down (e.g., at night), but there is no rāga–dveṣa, no attachment–aversion in it.

In both, the key point: Any bodily position is completely free from passions; there is only equanimity and omniscience.

---

3. Does a kevalgyani smile?

We must distinguish outer face vs inner emotions.

Inner side (both traditions):

• No rāga (attachment), no dveṣa (aversion), no excitement, no mental ups–downs.
• So they do not smile out of:

- joke, pride, liking/disliking, victory, etc.

• Inside there is same calm, equal vision to all jivas.

Outer side:

• Jain texts and traditional descriptions do speak of prasannatā – a serene, pleasant, peaceful face of Arihants.
• So:

- The face is peaceful, gentle, “smiling” in the sense of serenity. - Not a worldly, emotional smile due to some event.

Digambar:

• Generally emphasizes complete stillness;

any smile is understood as the natural serenity of a passionless face, not as changing expressions.

Shwetambar:

• More easily describes Tirthankar’s compassionate, serene smile,

yet still without inner attachment or mental disturbance.

So: Kevalgyani can have a calm, serene, “smiling” appearance, but never a worldly smile born from excitement or emotions.

---

In essence:

• Sukh: Only infinite, inner spiritual bliss – always present.
• Lying down:

- Digambar – no lying down after kevalgyan (only kayotsarga). - Shwetambar – may lie down, but fully detached.

• Smile:

- Inner state: no emotional smile at all. - Outer: a naturally serene, peaceful, “smiling” face.

For a simple explanation of kevalgyan itself, you can read more here