AS LONG AS I am in the world, I am the light of the world

Did Jesus say that when he was not in the world, he was not the light of the world?

No. Let's see the context. In the third and the final year of Jesus' ministry in J 8:

12 Again Jesus spoke to them, saying, “I am the light of the world.

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There was no additional restriction of the above statement. Jesus talked ambiguously about his eternal nature.

Whoever follows me will not walk in darkness, but will have the light of life.”

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But then, he also pointed out his physical nature:

21 So he said to them again, “I am going away, and you will seek me, and you will die in your sin. Where I am going, you cannot come.”

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Jesus knew soon he would die on the cross. He understood he had limited time to work during his earthly ministry. As long as He was physically present, He actively revealed God’s truth and performed miraculous works that point to his identity as the Messiah. Then he came across some work, J 9:

1 As he passed by, he saw a man blind from birth. 2 And his disciples asked him, “Rabbi, who sinned, this man or his parents, that he was born blind?” 3 Jesus answered, “It was not that this man sinned, or his parents, but that the works of God might be displayed in him. 4 We must work the works of him who sent me while it is day; night is coming, when no one can work. 5 As long as I am in the world, I am the light of the world.”

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The phrase "as long as" emphasized the urgency. Jesus stressed the temporary nature of his earthly ministry. He would die a few months later. Jesus acknowledged that his earthly ministry was finite. After his death, resurrection, and ascension, his physical presence will no longer be in the world in the same way.

6 Having said these things, he spit on the ground and made mud with the saliva. Then he anointed the man’s eyes with the mud 7and said to him, “Go, wash in the pool of Siloam” (which means Sent). So he went and washed and came back seeing.

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After His ascension, the light would continue through the work of the Holy Spirit, the apostles, and believers. Mt 5:

14 “You are the light of the world. A city set on a hill cannot be hidden. 15 Nor do people light a lamp and put it under a basket, but on a stand, and it gives light to all in the house. 16 In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven."

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Horizontally speaking, Jesus was the light of the world to carry out God's work. After his departure, his followers are the light of the world to carry out God's work. In this way, believers bear Jesus' light.

Did Jesus logically imply that when he was not in the world, he was not the light of the world?

No.

Let proposition P1 = If Jesus is physically (in the flesh) in the world, then he is the light of the world.

I.e., "As long as I am in the world, I am the light of the world."

Let proposition P2 = If Jesus is the light of the world, then he is physically (in the flesh) in the world.

P2 is the converse of P1, not its material implication. Jesus didn't say, "As long as I am the light of the world, I am in the world", i.e, if Jesus is the light of the world, then Jesus is physically in the world in the form of bodily flesh.

Yes, today, Jesus is still the light of the world, but we carry this light in us.